2. Calculate the force (in newtons) exerted on a rocket, given that the propelli

Question

2. Calculate the force (in newtons) exerted on a rocket, given that the propelling gases are expelled at a rate of 1400 kg/s, with a speed of 67000 m/s at takeoff.

3. A 17000 kg railroad car travels along on a level frictionless track with a constant speed of 23.0 m/s. A 5300 kg additional load is dropped onto the car. What then will be its speed in meters/second?

4. A 120 kg tackler moving at 3.0 m/s meets head-on (and tackles) a 98 kg halfback moving at 7.5 m/s. What will be their mutual velocity in meters/second immediately after the collision?

5. A 45 g bullet strikes and becomes embedded in a 1.46 kg block of wood placed on a horizontal surface just in front of the gun. If the coefficient of kinetic friction between the block and the surface is 0.28, and the impact drives the block a distance of 17.0 m before it comes to rest, what was the muzzle speed of the bullet in meters/second?

6. An atomic nucleus at rest decays radioactively into an alpha particle and a nucleus smaller than the original. What will be the speed of this recoiling nucleus if the speed of the alpha particle is 1.20E+05 m/s? Assume the recoiling nucleus has a mass 51 times as great as that of the alpha particle.

7. A tennis ball may leave the racket on a serve by a top player with a speed of 45.0 m/s. If the ball's mass is 0.065 kg, and it is in contact with the racket for 0.030 s, what is the average force (in newtons) on the ball?

8. A 170 kg astronaut (including space suit) acquires a speed of 2.15 m/s by pushing off with his legs from a 2600 kg space capsule. What is the average change in speed in meters/second of the space capsule?

Explanation / Answer

here,

rate at which propelling gases are expelled , r = 1400 kg/s

the speed at take off , v = 67000 m/s

let the force exerted an the rocket be F

using second law of motion

force = rate of change of momentum

F = v* rate of gases expelled

F = 67000 * 1400

F = 93800000 N

the force exerted on the rocket is 9.38 * 10^7 N

please ask seprate question in seprate posts

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