An object of mass 20 kg, initially at rest, is pulled along a rough horizontal surface by a force of 80 N acting at an angle of 40° upwards from the horizontal. A friction force of 20 N opposes the motion.
After the pulling force has acted for 5 seconds, the magnitude of the momentum, in kg ms−1, of the object is closest to
- 10
- 40
- 160
- 210
- 4100