Answer:
<em>The speed of the plane after it decelerates is 50 m/s</em>
Explanation:
<u>Motion with Constant Acceleration</u>
When an object gains or losses velocity in time, it acquires acceleration. If this value is constant, we can calculate the final velocity (or speed in scalar terms) as:

Where vf is the final speed, vo is the initial speed, a is the constant acceleration, and t is the time the acceleration is acting.
The plane is originally traveling at vo=80 m/s and it slows down at a constant rate of
during t=120 seconds. Note we have added the negative sign to the acceleration because the plane is slowing down, i.e., the acceleration is against the speed.
Thus, the final speed is:



The speed of the plane after it decelerates is 50 m/s
Answer:
a) Δp = -2.0 kgm / s, b) Δp = -4 kg m / s
Explanation:
In this exercise the change in moment of a ball is asked in two different cases
a) clay ball, in this case the ball sticks to the door and we have an inelastic collision where the final velocity of the ball is zero
Δp = p_f - p₀
Δp = 0 - m v₀
Δp = - 0.100 20
Δp = -2.0 kgm / s
b) in this case we have a bouncing ball, this is an elastic collision, as the gate is fixed it can be considered an object of infinite mass, therefore the final speed of the ball has the same modulus of the initial velocity, but address would count
v_f = - v₀
Δp = p_f -p₀
Δp = m v_f - m v₀
Δp = m (v_f -v₀)
Δp = 0.100 (-20 - 20)
Δp = -4 kg m / s
I can answer it in the comments, but can i ask what i’m supposed to do exactly? i remember learning about this stuff but i need the instructions.