If a ball with a momentum of 40 kgm/s has a velocity of 2 m/s, what is its mass?
momentum (m)=40
velocity (v)=2
now,
momentum (m)=m×v
40=m×2
m=40÷2
m=20kg
You throw a baseball a distance of 20 meters. Is it work or not work?
A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the building at a speed of 1.1 m/s, how fast is the length of his shadow on the building decreasing when he is 4 m from the building
Answer:
[tex]\frac{dh}{dt}=-0.4125 m/s[/tex]
Explanation:
The very first thing we can do here is to draw a sketch of the situation the problem is presenting. (See attached picture)
As you may see in the picture, we can suppose the spotlight is directly located on the ground so the light of the spotlight together with the person and the wall make two similar triangles.
In this case we need to think about the dimensions of the triangle that will change over time. We will call them:
x= distance between the spotlight and the man.
h= height of the shadow.
So we can build a relation between the height and the length of each triangle:
[tex]\frac{h}{12}=\frac{2}{x}[/tex]
the distance between the spotlight and the wall is constant, so I can directly write the 12 in my equation and the height of the man is constant as well, so I can write the 2 directly into the equation.
Next, we can solve the equation for h (since we are interested in figuring out how fast the height of the shadow is decreasing) so we get:
[tex]h=\frac{24}{x}[/tex]
So next, we need to take the derivative of the equation, since the derivative of a position function will give us the velocity at which that position is changing.
First we rewrite the equation like this:
[tex]h=24x^{-1}[/tex]
and take the derivative:
[tex]dh=-24x^{-2}dx[/tex]
we can rewrite the derivative like this:
[tex]\frac{dh}{dt}=-\frac{24}{x^{2}} \frac{dx}{dt}[/tex]
where:
dh/dt is the velocity at which the height of the shadow is decreasing (that's why our equation has a negative sign in front of it).
dx/dt is the velocity at which the value of x is increasing. In other words, how fast the man is moving away from the spotlight.
So we can go ahead and substitute:
we wish to find the velocity at which the shadow's height is decreasing when the distance between the man and the building is 4m, so in this case, x=12-4=8m
[tex]\frac{dh}{dt}=-\frac{24}{8^{2}}(1.1 m/s)[/tex]
so we get:
[tex]\frac{dh}{dt}=-0.4125 m/s[/tex]
A 755 N box rests on a floor with a coefficient of kinetic friction of 0.600 and a coefficient of static friction of 0.800. What horizontal force is required to start the box moving
Answer:
fr = R× co-efficient
= 755 × 0.80
= 604N
Explanation:
A different bullet has a mass of 0.09 kg. Starting from rest, after its gun's trigger is pulled, a constant force acts on the bullet for the next 0.025 seconds until the bullet leaves the barrel of the gun with a speed of 1,346 m/s.
What force acts on this bullet?
The force acts on this bullet : 4.8456 N
Further explanationGiven
m=0.09 kg
Δt=0.025 s
vo=0(from rest)
vt=1.346 m/s
Required
Force
Solution
Impulse is a change in momentum
I=ΔP
F.Δt=m(vt-vo)
Input the value
F x 0.025 = 0.09(1.346-0)
F=4.8456 N
A 1.5kg object moving with a speed of 2.5m/s strikes a wall and the ball rebounds with a speed of 1.5m/s. The ball is in contact with the wall for 0.045s. What is the magnitude of the average force exerted on the ball by the wall?
Answer:
F = 133.33[N]
Explanation:
This problem can be solved by the principle of momentum conservation, which tells us that momentum is preserved before and after the bounce of the ball on the wall.
In such a way that the movement towards the wall we will take it with a positive sign, and the force of the rebound to the left as negative. The movement to the left will be taken as a negative sign.
[tex]m_{1}*v_{1}-F*t=-m_{1}*v_{2}[/tex]
where:
m₁ = mass of the object = 1.5 [kg]
v₁ = velocity of the ball before hitting the wall = 2.5 [m/s]
F = average force [N]
t = time contact = 0.045 [s]
v₂ = velocity of the ball after hitting the wall = 1.5 [m/s]
Now replacing:
[tex](1.5*2.5)-F*0.045=-(1.5*1.5)\\3.75+2.25=F*0.045\\F=6/0.045\\F=133.33[N][/tex]
A sled with a mass of 20 kg is sliding along the snow with a velocity of 5 m/s. What is the momentum of the sled?
Question 7 options:
100 kg/ms
4 kg/ms
15 kg/ms
25 kg/ms
Answer:
100kgms⁻¹
Explanation:
Given parameters:
Mass of the sled = 20kg
Velocity of the sled = 5m/s
Unknown:
Momentum of the sled = ?
Solution:
The momentum of a body is the quantity of motion such a body possesses. Due to this;
Momentum = mass x velocity
Now insert the parameters and solve;
Momentum = 20 x 5 = 100kgms⁻¹
If a wheel rotates 5 times in 90 seconds, what is the period and frequency
Answer:
i think it should be 18
Explanation:
what is the electrical potential at the surface of gold nucleus? The radius of a gold atom is 6.6*10
Complete question is;
What is the electrical potential at the surface of gold nucleus? The radius of a gold atom is 6.6 × 10^(-5) m and atomic number z = 79.
Answer:
172.36 × 10^(-5) V
Explanation:
We are given;
Radius; r = 6.6 × 10^(-5) m
Atomic number; Z = 79
Formula for Electric potential here is;
V = kZe/r
Where;
e is charge on proton = 1.6 × 10^(-19) C
k has a constant value of 9 × 10^(9) N⋅m²/C²,
Thus;
V = (79 × 1.6 × 10^(-19) × 9 × 10^(9))/(6.6 × 10^(-5))
V = 172.36 × 10^(-5) V
A woman holds a frozen smoothie in her hand on a warm
day.
Which photo shows the direction of thermal energy transfer?
O A.↕️
B
C ⬆️
D⬇️
Answer:
C
Explanation:
The thermal energy from her hand will go up into the smoothie.
Answer:
C bois
Explanation:
Water is found as a solid, liquid, and gas on ____.
Essential Questions: What does the particle theory tell us about the nature of matter? How does
each state of matter behave?
sowwie :( i need points
Explanation:
A boy walked 4m east then 3m south find the displacement
Answer:
5m
Explanation:
[tex]4^{2}+3^{2}=5^{2}\\5^{2}=25[/tex]
Use the Pythagorean theorem to calculate the long edge of the triangle, which would be his displacement.
true or false
Almost all of Earth's atmosphere is created through the process of photosynthesis.
Answer:
true
Explanation:
I believe the answer i chose because the earths atmosphere is mostly made up of different things that causes the earth to interact with human life and also interacts with what's in the atmosphere like energy oxygen carbon dioxide and all the stuff like that i hope its right.
2 benefits of yoga with explanation
A 0.41kg football that is initially at rest acquires a velocity of 35m/s when it is kicked. If the kicker's boot remains in contact with the ball for 0.08s, what is the average force of the kick?
Answer:
F = 318.88[N]
Explanation:
This problem can be solved by the principle of momentum conservation, which tells us that momentum is preserved before and after kicking the ball.
In this way, we can construct the following equation.
[tex]F*t=m*v[/tex]
where:
F = force [N]
t = time = 0.08 [s]
m = mass = 0.41 [kg]
v = velocity [m/s]
[tex]F*0.045=0.41*35\\F=318.88[N][/tex]
A horizontal force of 5.0-N accelerates a 4.0-kg mass, from rest, at a rate of 0.50 m/s^2 in the positive direction. What friction force acts on the mass
Answer:
3N
Explanation:
The frictional force always acts directly opposite to the force of motion, that is it opposes motion. According to the Newton second law of motion:
Sum of horizontal forces = 0
Hence:
5N - 4(0.5) - F = 0
5 - 2 = F
F = 3N
Victor covers 210 km by car at a speed of 70 km/hr. find the time taken to cover this distance.
Answer:
3 hrs
Explanation:
the distance covered by victor= 210 km
speed= 70 km/hrs
so, 70×3= 210
so the answer is 3 hrs
BTW im a small kid so don't just right away say the explanation sucks and the subject physics is not yet started in my grade.
edit: don't give me brainless answer plz.
11. Which element in Figure 15.17 is likely to be a the best conductor of electricity ?
Answer:
first where is figure...
silver the is best conducter of electricity.
a suspension bridge cable is connected to its anchor at a 20 degree angle. calculate the vertical component force on the anchor by the cable.
The question is missing some parts. Here is the complete question.
A suspension bridge cable is connected to its anchor at a 20° angle. Find the vertical and horizontal component of the force on the anchor by the cable.
Answer: [tex]F_{x}=[/tex] 14095.4 N
[tex]F_{y}=[/tex] 5130.3 N
Explanation: The force applied to the anchor is not perpendicular to the horizontal plane. So, it can be decomposed into 2 components: a vertical component, which is on the y-axis, and a horizontal component, which is on the x-axis.
The force and its components forms a right triangle, so we can calculate the components by using trigonometric relations:
Horizontal
[tex]cos(20)=\frac{F_{x}}{F}[/tex]
[tex]F_{x}=F.cos(20)[/tex]
[tex]F_{x}=15,000(0.9397)[/tex]
[tex]F_{x}=[/tex] 14,095.4 N
Vertical
[tex]sin(20)=\frac{F_{y}}{F}[/tex]
[tex]F_{y}=Fsin(20)[/tex]
[tex]F_{y}=[/tex] 15,000(0.3420)
[tex]F_{y}=[/tex] 5,130.3 N
The vertical and horizontal components of force on the anchor by the cable are 5130.3 N and 14095.4 N, respectively.
what is kinetic energy
Answer:
Kinetic energy is energy of motion
Explanation:
Of potential energy which is energy that is stored
Calculate, for the judge, how fast you were going in miles per hour when you ran the red light because it appeared Doppler-shifted green to you. Take red light to have a wavelength of 650 nm and green to have a wavelength of 550 nm.
Answer:
The doppler effect equation is:
[tex]f' = \frac{v +v0}{v - vs}*f[/tex]
In the equation we have frequencies, but then we have the wavelengths of the lights, remember the relation:
v = f*λ
then:
f = v/λ
and v is the speed of light, then:
f = c/λ
where:
f' is the observed frequency, in this case, is equal to f = (3*10^17nm/s)/550 nm
f is the real frequency, in this case, is (3*10^17nm/s)/650 nm
vs is the speed of the source, in this case, the source is not moving, then vs = 0 m/s.
v is the speed of the wave, in this case, is equal to the speed of light, v = 3*10^8 m/s
v0 is your speed, this is what we want to find.
Replacing those quantities in the equation, we get:
(3*10^17nm/s)/550 = (3*10^8 m/s + v0)/(3*10^8 m/s)*(3*10^17nm/s)/650 nm
(650nm)/(550nm) = (3*10^8 m/s + v0)/(3*10^8 m/s)
1.182*(3*10^8 m/s) = (3*10^8 m/s + v0)
1.182*(3*10^8 m/s) - (3*10^8 m/s) = v0 = 54,600,000 m/s
So your speed was 54,600,000 m/s, which is a lot.
A woman does 236 J of work
dragging her trash can 24.4 m to
the curb, using a force of 18.9 N.
At what angle was her force
directed?
Answer:
workdone = force × distance 236J = 18.9cos(o) × 24.4236/24.4 = 18.9cos(o)(0.5117)cos^-1 = (o)59.21°Four charges of equal magnitude, q = +1 uC, are placed at the four corners of a square with a side length of 1 meter located in the xy-plane. A small ball with a known charge +2 uC and an unknown mass is placed 2 meters above the center of the square (so along the z-axis).
Required:
a. What is the total force on the small ball from the four charges?
b. If the ball is in equilibrium where it was placed and we assume standard earth gravity, 9.8 m/s^2, what must the mass of the ball be?
Answer:
a) F _total = 15.08 10⁻³ N , b) m = 1,539 10⁻³ kg
Explanation:
a) To solve this problem we can use Coulomb's law to find the force created by each charge
F =[tex]k \frac{\ q_{1} q_{2} }{r_{12}^{2} }[/tex]
and the total force is
F = F₁₅ + F₂₅ + F₃₅ + F₄₅
The bold are vectros, In the exercise they indicate the charges
q₁ = q₂= q₃ = q₄ = 1 10⁻⁶ C
q₅ = 2 10⁻⁶ C
Let's set a reference system where the sphere is on the z axis and the other charges on the xy plane, let's write the coordinates of card charge
sphere (subscript 5)
x₅ = 0
y₅ = 0
z₅ = 2 m
charge 1
x = 0.5 m
y = 0.5 m
z = 0
charge 2
x = -0.5 m
y = 0.5 m
z = 0
charge 3
x = -0.5 m
y = -0.5 m
z = 0
charge 4
x = 0.5 m
y = -0.5 m
z = 0
With these values we can calculate the distance between each charge and the sphere
charge 1 and sphere
r₁₅² = (x₅ -x₁)² + (y₅ - y₁)² + (z₅ -z₁)²
substitute
r₁₅² = (0- 0.5)² + (0 - 0.5)² + (2 -0)²
r₁₅² = 0.5² + 0.5² + 2²
r₁₅² = 4.5
we can see that for the other charges the result is the same since being squared always gives positive
r₁₅ = r₂₅ = r₃₅ = r₄₅
the force created by the card charge on the sphere is the projection on the Z axis of the total force
Let's find the angle with respect to the Z axis
tan φ = r / z
where r is the magnitude of the vector in the xy plane
r = [tex]\sqrt{0.5^{2} + 0.5^{2} }[/tex]
r = 0.7071 m
φ = tan⁻¹ r / z
φ = tan⁻¹ (0.7071 / 2)
φ = 19.5
consequently the total force is
F_total = 4 F cos 19.5
F _total = [tex]4 \frac{k \ q_{1} q_{5} }{r_{15}^{2}}[/tex] cos 19.5
let's calculate
F_toal = 4 9 10⁹ 1 10⁻⁶ 2 10⁻⁶ /4.5 cos 19.5
F _total = 15.08 10⁻³ N
b) For this part indicate that the sphere is in equilibrium with the weight
F_total - W = 0
W = mg
F_total = mg
m = F_total / g
m = 15.08 10³ / 9.8
m = 1,539 10⁻³ kg
A zone plate is found to give series of images of a point source on its axis. If the strongest and the second strongest images are at distances of 0.30m and 0.06 m respectively from the zone plate (both from the same side remote from the source), calculate the distance of the source from the zone plate, principal focal length and the radius of the second zone. Assume λ = 6 x 10-7m.
A 3.6kg cat is laying on a tree branch, 3 meters above the ground. What is the cat’s potential energy?
Answer:
E = 105.84 J
Explanation:
Given that,
Mass of cat, m = 3.6 kg
It is laying 3 meters above the ground.
We need to find the cat's potential energy. The formula for the potential energy of an object is given by :
E = mgh
Substituting all the values,
E = 3.6 kg × 9.8 m/s²×3 m
E = 105.84 J
So, the cat's potential energy is 105.84 J.
PLEASE ANSWER QUESTION 7!!!! PLEASE
Answer:
Explanation:
The force of gravity depends directly upon the masses of the two objects, and inversely on the square of the distance between them. This means that the force of gravity increases with mass, but decreases with increasing distance between objects
so a option is correct
Two ice skaters stand together. They push off and travel directly away from each other, the boy with a velocity of v = +0.35 m/s. If the boy weighs 745N and the girl 477 N, what is the girl's velocity after they push off? ( Consider the ice to be frictionless)_____m/s
Answer:
-0.55m/s
Explanation:
Given that: For the boy
Weight = 745N
Velocity = +0.35 m/s
Mass of the boy = ?
g = 9.81m/s^2
W = mg
745 = m×9.81
m = 75.94kg
For the girl
Given that:
Weight = 477 N
g = 9.81m/s^2
m = ?
W = mg
477 = m×9.81m/s^2
m = 48.62kg
To solve for the v of the girl, the two has to add up
48.62kg×v + 75.94kg×+0.35 m/s = 0
48.62v + 26.579 = 0
48.62v = - 26.579
v = -26.579/48.62
v = -0.5466
v = -0.55m/s
Hence, the velocity of the girl is -0.55m/s.
The negative sign is as a result of the two of them moving is opposite direction.
How can the relationship between atomic number and the number of protons be described?
Answer:
It's the number of protons in the nucleus of the atom
A water balloon is dropped off the top of a building and bursts when it hits
the ground 6 seconds later. What is the height of the building?
Answer:
The building is 176.4 meters high.
Explanation:
We use the formula for kinematics of an accelerated object (in this case acceleration of gravity):
Distance travelled = 1/2 g t^2
Distance travelled = 1/2 9.8 (6)^2 = 176.4 meters