A 1 200-kg experimental rocket sled on level frictionless rails is loaded with 55.0 kg of propellant.It exhausts the propellant in a 20-s "burn." If the rocket,initially at rest,moves at 155 m/s after the burn,what impulse is experienced by the rocket sled?
A)8.5E+3 kg⋅m/s
B)1.3E+5 kg⋅m/s
C)1.9E+5 kg⋅m/s
D)8.5E+5 kg⋅m/s
E)2.1E+5 kg⋅m/s

Question

Quizplus · Accepted Answer

We can start by using the principle of conservation of momentum, which states that the total momentum before and after the burn must be equal. Before the burn, the rocket sled is at rest, so its momentum is 0 kg⋅m/s. After the burn, the rocket sled has a mass of 1 200 kg + 55.0 kg = 1 255 kg and a velocity of 155 m/s. Therefore, its momentum is:

p = m*v = (1 255 kg)*(155 m/s) = 194 525 kg⋅m/s

To find the impulse experienced by the rocket sled, we need to calculate the change in momentum. This is:

Δp = p_f - p_i = 194 525 kg⋅m/s - 0 kg⋅m/s = 194 525 kg⋅m/s

Therefore, the impulse experienced by the rocket sled is 194 525 kg⋅m/s, which is closest to choice C (1.9E+5 kg⋅m/s).

A 1 200-Kg Experimental Rocket Sled on Level Frictionless Rails