Answer:
h = 3.5 m
Explanation:
First, we will calculate the final speed of the ball when it collides with a seesaw. Using the third equation of motion:

where,
g = acceleration due to gravity = 9.81 m/s²
h = height = 3.5 m
vf = final speed = ?
vi = initial speed = 0 m/s
Therefore,

Now, we will apply the law of conservation of momentum:

where,
m₁ = mass of colliding ball = 3.6 kg
m₂ = mass of ball on the other end = 3.6 kg
v₁ = vf = final velocity of ball while collision = 8.3 m/s
v₂ = vi = initial velocity of other end ball = ?
Therefore,

Now, we again use the third equation of motion for the upward motion of the ball:

where,
g = acceleration due to gravity = -9.81 m/s² (negative for upward motion)
h = height = ?
vf = final speed = 0 m/s
vi = initial speed = 8.3 m/s
Therefore,

<u>h = 3.5 m</u>
Answer:
0
Explanation:
Forces with equal magnitudes and opposite directions cancel each other out, so the net force is 0.
Answer:
They will move the fridge if they all push in the same direction, but it will not move with constant velocity
Explanation:
The maximum static friction force is
(negative sign since its direction is opposite to the push applied by the people)
Sam can apply a force of 130 N, while Amir and Andre can apply a push of 65 N each, so the total force that they can apply, if they push in the same direction, will be:

This force is larger than the frictional force, so the fridge will start moving.
However, the net force on the fridge will be:

And according to Newton's second law,

where m is the mass of the fridge and a its acceleration, since the net force is not zero, then the fridge will have a non-zero acceleration, so it will not move with constant velocity.
Velocity is displacement/time
(Displacement is the overall change in distance)
So you’ll want to divide 200 by 25, which should give you:
8 m/s