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. A falling rubber ball of mass 0.025 kg strikes the ground traveling straight down at 4.0 m/s. Find the magnitude of the impulse that the ground gives to the ball if

a) the ground is soft and the ball stops dead

b) the ground is hard and the ball bounces straight back at 2.0 m/s.

2 Answers

4 votes

Final answer:

In Physics, the impulse provided to a 0.025 kg ball striking the ground at 4.0 m/s is 0.1 kg·m/s when it stops, and 0.15 kg·m/s when it bounces at 2.0 m/s, with impulse being equivalent to the change in momentum.

Step-by-step explanation:

The subject of the question falls under Physics, specifically the topic of impulse and its relationship with force and momentum. Impulse is defined as the change in momentum of an object when it is subjected to a force over time.

To find the impulse given to the ball in both scenarios, we will use the formula for impulse, which is the product of the average force and the time interval during which the force acts. Impulse can also be calculated by the change in momentum, where momentum is given by the product of the mass and velocity of the object.

  • For scenario (a), where the ball stops, the impulse is simply the negative of the initial momentum since the final velocity is zero: Impulse = 'Final Momentum - Initial Momentum' = '0 kg·m/s - (0.025 kg ' 4.0 m/s)' = -0.1 kg·m/s.
  • For scenario (b), where the ball bounces back, Impulse = 'Final Momentum - Initial Momentum' = '(0.025 kg ' (-2.0 m/s)) - (0.025 kg ' 4.0 m/s)' = -0.15 kg·m/s (The negative sign indicates a direction opposite to the initial momentum).

The magnitude of the impulses would be 0.1 kg·m/s for the ball stopping and 0.15 kg·m/s for the ball bouncing back, without considering the direction.

User Inneb
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5.1k points
6 votes

Given that,

Mass of the ball, m = 0.025 kg

Initial speed, u = 4 m/s

To find,

Impulse when (a) the ground is soft and the ball stops dead

(b) the ground is hard and the ball bounces straight back at 2.0 m/s.

Solution,

Impulse = change in momentum

J = m(v-u)

(a) u = 0 (as it stops)

J = 0.025(4-0)

J = 0.1 N-m

(b) v = 2 m/s

J = 0.025(4-2)

= 0.05 N-m

Therefore, this is the required solution.

User Jonafato
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5.1k points