1: An object is falling freely under gravity. How much distance will it travel 2nd and 3rd second of its journey? (Ans. 15 m, 25 m)

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2: A helicopter is ascending vertically at a speed of 19.6 m/s. When it is a height of 156.8 m above the ground, a stone is dropped. How long does the stone take to reach the ground? (Ans. 8.05 m)



3: A car moving at 20.0 m/s (72.0 km/h) crashes into a tree. Find the magnitude of the average force acting on a passenger of mass 70 kg in each of the following cases. (a) The passenger is not wearing a seat belt. He is brought to rest by a collision with the windshield and dashboard that lasts 2.0 ms. (b) The car is equipped with a passenger-side air bag. The force due to the air bag acts for 45 ms, bringing the passenger to rest.

4: A 0.4 kg ball traveling with the speed of 15 m/s strikes a rigid wall and rebounds elastically. If the ball is in contact with the wall for 0.045 s, what is (a) the momentum imparted to the wall and (b) the average force exerted on the wall? (Ans. 12 kg m/s, 266.7N)

5: One ball of mass 0.600 kg traveling 9.00 m/s to the right collides head on elastically with a second ball of mass 0.300 kg traveling 8.00 m/s to the left. After the collision, what are their velocities after collision? (Ans. -2.33 m/s (2.33 m/s to left) and 14.67 m/s (14.76 m/s to right))

6: In a wedding a bullet is fired in air at a speed of 500 m/s making an angle of 60' with horizontal from an AK 47 rifle. (a) How high will the bullet rise? (b) What time would it take to reach ground? (c) How far would it go? (Ignore air resistance)((a) 9,560 m (b) 88.3 s (c)22,078 m)


7: The catapult hurls a stone of mass 32.0 g with a velocity of 50.0 m/s at a 30.0' angle of elevation. (a) What is the maximum height reached by the stone? (b) What is its range? (c) How long has the stone been in the air when it returns to its original height? (Ans. (a) 31.87 m (b) 5.1 s (c) 220.8m)

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