A 1.2 kg ball drops vertically onto a floor, hitting with a speed of 25 m/s. It rebounds with an initial speed of 10 m/s. a) What impulse acts on the ball during the contact? b) If the ball is in contact with the floor for 0.020 s, what is the magnitude of the average force on the floor from the ball? c) why is 25m/s "negative" ? why is it considered the initial velocity yet it will be considered negative?

A 160 g ball strikes a vertical wall and bounces off. The ball's initial velocity is a horizontal 5 m/s and the wall imparts an average normal force of 6.4 N for a time of 0.15 seconds during the bounce. What is the ball's final velocity (include magnitude and direction)? Use the impulse-momentum theorem to solve.

A ball of mass 0.160 kg is dropped from rest from a height of 1.25 m. It rebounds from the floor to reach a height of 0.870 m. What impulse was given to the ball by the floor? magnitude direction

In a softball game, a 0.2 kg ball crosses the plate at 10 m/s at an angle of 45° on its way down. The batter hits the ball toward center field, giving it a velocity of 45 m/s at 30° above the horizontal. a. Determine the impulse given to the ball. b. If the force on the ball increases linearly for 4 ms, holds constant for 20 ms, and then decreases to zero linearly in another 4 ms. i) What is the average force on the ball? ii) What is the peak force on the ball? 4

A 51 kg boy on roller skates moves with a speed of 3 m/s. He runs into a 42 kg girl on skates. Assuming they cling together after the collision, what is their speed (in m/s)? (Assume the girl is initially at rest.) m/s

Question Three

An estimated force vs. time curve for a baseball struck by a bat is shown in the figure below. Fmax 18000 N F (N) 20 000 15 000 10 000 5 000 0 t (ms) 0 1 2 (a) From this curve, determine the impulse delivered to the ball. L N - s (b) From this curve, determine the average force exerted on the ball. KN

In the overhead view of the figure, a 275 g ball with a speed v of 4.0 m/s strikes a wall at an angle of 30° and then rebounds with the same speed and angle. It is in contact with the wall for 13.5ms. (a) What is the impulse on the ball (take positive as down in the figure)?

Question 140 to 144

A 0.2-kg rubber ball is dropped from the window of a building. It strikes the sidewalk below at 30m/s and rebounds up at 20m/s. The impulse on the ball during the collision is: A 10N · s upward B) 10N · s downward c) 2.0N · s upward D) 2.0N · s downward