Question

Question 3

If a 8 kg mass, moving at 7 m/s to the right, hits and sticks to a 18 kg mass, moving at 20 m/s to the right, and they travel off together at the same speed to the right, find that speed.

Hint: both masses are moving to the right, so both velocities are positive. Use the "hit and stick" or inelastic formula

Question 4

If a 11 kg mass, moving at 7 m/s to the right, hits and sticks to a 20 kg mass, moving at 4 m/s to the left, and they travel off together at the same speed, find that speed.

Hint: here, the masses are moving in opposite directions, so the velocities should have opposite signs. Call "to the right" positive and "to the left" negative. Use the "hit and stick" or inelastic formula.

Question 5

If a 1848 kg car, moving at 7 m/s north, hits and sticks to a 2250 kg truck, moving at 5 m/s south, and they travel off together at the same speed, find that speed.

Hint: here the masses are moving in opposite directions, so the velocities should have opposite signs. Call North positive and South negative. Use the "hit and stick" or inelastic formula

Also, a positive answer would indicate motion to the north and a negative answer would show southward motion - leave positive/negative in your answer.

Question 6

If a 1277 kg car, moving at 10 m/s north, hits and sticks to a 3269 kg truck, moving at 7 m/s east, find the magnitude of the final speed.

Hint: here the masses are moving north and east (or in the x & y directions) - so it's a two dimensional problem. Just like all other two dimensional problems we need to separate the x and y motions, treat each separately, and the put the two directions back together. Use the "hit and stick" or inelastic formula

• use the inelastic collision formula in the x-dir, only using the x-components of the two velocities
• use the inelastic collision formula in the y-dir, only using the y-components of the two velocities
• use the Pythagorean Theorem to combine the x & y components so as to get the magnitude of the final velocity
• use arcTan(v_y' / v_x') to get the direction of the final velocity
• if the angle doesn't end up in the first quadrant, then fix the angle

Question 7

If a 1556 kg car, moving at 6 m/s north, hits and sticks to a 3193 kg truck, moving at 10 m/s west, find the direction of the final speed.

Hint: two dimensional problem.

Question 8

If a 1220 kg train car on a one dimensional track, moving at 10 m/s north, hits and bounces off a second train car with a mass of 2338 kg , moving at 10 m/s south, find the magnitude of the final speed of the first car (the second car will have a different speed, most probably in the opposite direction).

Hint: One dimensional problem, call north positive. Use the "hit and bounce" or elastic formula that goes with car #1

Also, a positive answer would indicate motion to the north and a negative answer would show southward motion - leave positive/negative in your answer.

Question 9

If a 9 kg bowling ball, moving at 15 m/s to the right, hits and bounces off a second bowling ball with a mass of 11 kg , moving at 10 m/s to the left, find the magnitude of the final speed of the second ball.

Answer 1