A metal ball with a mass of 20 g falling at a speed of 5 m / s hit a steel plate and bounced off it with the same speed model. Find the change in momentum of the ball,
m = 20 grams is the mass of the metal ball;
v1 = 5 m / s (meters per second) – the speed with which the metal ball was moving.
It is required to determine dp (kg * m / s) – the change in the momentum of the ball after it hit the steel plate and rebounded from it.
Let’s convert the units of measurement of mass to the SI system:
m = 20 grams = 20 * 10-3 = 20/1000 = 0.02 kilograms.
According to the condition of the problem, the ball bounced off the plate with the same speed in absolute value, that is, v2 = | v1 | = -v1.
dp = p1 – p2 = m * v1 – m * v2 = m * v1 + m * v1 = 2 * m * v1 = 2 * 0.02 * 5 = 2 * 0.1 = 0.2 kg * m / s …
Answer: the change in the momentum of the ball is 0.2 kg * m / s.
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