A ball of mass 0.7 kg strikes the wall at an angle of 90 degrees with speed 72 km/h. Consider that the bounce lasts for 0.1 s and is perfectly elastic. What is the magnitude of the average reaction force from the wall that acts on the ball?
initial speed: v = 72 km/h = 20 m/s.
mass: m = 0.7 kg
time of the impact: t = 0.1 s
average force: F
The speed after impact is the same as initial speed, but velocity has got the opposite direction. Therefore, Δv = 2v
Δmomentum = Δp = mΔv = 2mv
from the Newton's 2nd Law:
F = Δp/Δt = 2mv/t
F = 20.720/(0.1) = 280 N
Answer: The magnitue of the average force equals 280 N.
FM
Related Physics A Level answers
All answers ▸Can you explain the photoelectric effect?
In the Photoelectric Effect, what is mean by 'threshold frequency' and how does the magnitude a photons frequency effect the electron it is absorbed by?
What is the de Broglie wavelength of a dust particle that has a mass of 1e-10 kg and a velocity of 0.05m/s?
Can you explain the Work-Energy principle and how you can apply it in a simple situation such as a box sliding down a rough slope?