Question

miniature spring-loaded, radio-controlled gun is mounted on an air puck. The gun's bullet has a mass of 5.00 g, and the gun and puck have a combined mass of 120 g. With the system initially at rest, the radio controlled trigger releases the bullet causing the puck and empty gun to move with a speed of 0.500 m/s. What is the bullet's speed

Answer 1

Answer:

12 m/s

Explanation:

From the question,

Applying the law of conservation of momentum,

total momentum before collision = Total momentum after collision

mu+Mu' = mv+Mv'........................... Equation 1

Where m = mass of the bullet, u = initial velocity of the bullet, M = combined mass of the gun and the puck, u' = initial velocity of the gun and the puck, v = final velocity of the bullet, v' = final velocity of the gun and the puck

make v the subeject of the equation

v = [(mu+Mu')-Mv']/m................. Equation 2

Given: m = 5.00 g = 0.005  kg, M = 120 g = 0.12 kg, u = u' = 0 m/s (at rest), v' = 0.5 m/s

Substitute these values into equation 2

v = [0-(0.12×0.5)]/0.005

v = -0.06/0.005

v = -12 m/s

The negative sign  can be ignored since we are looking for the speed, which has only magnitude.

Hence the speed of the bullet is 12 m/s