A person climbing the stairs and reaching the third floor.
If the mass of the person is 60 kg and the vertical height of the stairs he climbed is 15 m and the angle of inclination is 30 degrees, the potential energy at the top of the third floor is:
A. 4410 J
B. 4000 J
C. 8820 J
2. A ball of mass 25 grams is at rest at a height of 25 m from the ground. If the ball rolls down to the ground, calculate the kinetic energy just before it touches the ground. Assume negligible friction between the surfaces.
A. 22 J
B. 0.63 J
C. 6.13 J
3. An object of mass 0.045 kg is thrown at a wall with an initial velocity of 2 m/s. The ball is in contact with the wall for 0.006 seconds and bounces back with a velocity of 1.5 m/s. The force of impact is:
A. -26.25 N
B. 0.1575 N
C. -2.63 N
4. Two cars A and B of masses 1000 kg and 2000 kg moving in opposite directions with initial velocities +20 m/s and -30 m/s collide and they stick together. The final velocity of the cars after collision is:
A. 15 m/s
B. -13.3 m/s
C. 26.6 m/s