2017+Momentum

Monday





__ANSWERS__

page 209

1) 2482 kgm/s 2a) 121.05 kgm/s 2b) 94.5 kgm/s 2c) 26.55 kgm/s 3) 46.49 m/s

page 211

1) -375 N 2) We need to find the velocity that he hits the water with first, because that will be his momentum when he hits the water. So, using our motion equations we know that an object falling from a distance of 3 meters will be 7.67 m/s. So, momentum is 629 kgm/s. That drops to zero so the impulse is -629 kgm/s. So, divide that by time to get the force, which is -1144 N. It has to be negative because it's a stopping force. 3) Impulse = Pf - Pi. So, impulse = -16 kgm/s. (the final velocity was -22 m/s and the initial was 18 m/s) 4a) 9 m/s (Ft = change in momentum and the initial momenturm was zero) 4b) initial momentum = 4.5 kgm/s. The impulse provided by the force is 12 kgm/s in the opposite direction. So, the final momentum is -7.5 kgm/s. So, the final velocity is -15 m/s.

page 213

1) 13.75 m/s 2) 42.2 m 3) 8 seconds

page 214

1) doubled 2) 31.0 m/s 3) Not if the large force is given over a much smaller time comparitively. But, all things equal, a large force WOULD cause a greater change in momenturm because the change is equal to Ft 4) Momentum is a measure of the object's "mass in motion", or how much force it would take to stop the object. Impulse is the change in momentum due to some force either acting with the motion or opposing it. 5a) 2.52 kgm/s 5b) 126 N

Wednesday



ANSWER KEY:

1) 6.16 m/s 2) -6.67 m/s 3) 0.56 m/s 4) 14.11 m/s 5) 20.2 m/s 6a) 9 m/s 6b) it would have less final velocity or even be moving backward after the collision 7a) 0.35 m/s 7b) 42.5 s 8) 1.11 m/s

Thursday



Monday





Tuesday







Wednesday



Solve for the final velocity of the object and the direction it's moving: