Answer:
Drag or air resistance
Explanation:
The force of friction caused by a moving fluid is called drag. When that fluid is air, it's also known as air resistance.
Kinetic energy lost in collision is 10 J.
<u>Explanation:</u>
Given,
Mass,
= 4 kg
Speed,
= 5 m/s
= 1 kg
= 0
Speed after collision = 4 m/s
Kinetic energy lost, K×E = ?
During collision, momentum is conserved.
Before collision, the kinetic energy is

By plugging in the values we get,

K×E = 50 J
Therefore, kinetic energy before collision is 50 J
Kinetic energy after collision:


Since,
Initial Kinetic energy = Final kinetic energy
50 J = 40 J + K×E(lost)
K×E(lost) = 50 J - 40 J
K×E(lost) = 10 J
Therefore, kinetic energy lost in collision is 10 J.
Answer:
Distance covered by B is 4 times distance covered by A
Explanation:
For an object in free fall starting from rest, the distance covered by the object in a time t is

where
s is the distance covered
g is the acceleration due to gravity
t is the time elapsed
In this problem:
- Object A falls through a distance
during a time t, so the distance covered by object A is

- Object B falls through a distance
during a time 2t, so the distance covered by object B is

So, the distance covered by object B is 4 times the distance covered by object A.
The type of energy that depends on position is called
kinetic energy
Answer:
Approximately
. (Assuming that the drag on this ball is negligible, and that
.)
Explanation:
Assume that the drag (air friction) on this ball is negligible. Motion of this ball during the descent:
- Horizontal: no acceleration, velocity is constant (at
is constant throughout the descent.) - Vertical: constant downward acceleration at
, starting at
.
The horizontal velocity of this ball is constant during the descent. The horizontal distance that the ball has travelled during the descent is also given:
. Combine these two quantities to find the duration of this descent:
.
In other words, the ball in this question start at a vertical velocity of
, accelerated downwards at
, and reached the ground after
.
Apply the SUVAT equation
to find the vertical displacement of this ball.
.
In other words, the ball is
below where it was before the descent (hence the negative sign in front of the number.) The height of this cliff would be
.