10. A boy is playing with a toy sledge. In which surface will it travel fastes
A. The carpet
B. The rough floor
C. The wet floor
D. The polished floor
11. Which is used by the girl to produce motion in the bookshelf as show
A. Force
B. Friction
C. A pulley
D. Gravity
12. Which box would need the greatest force to move?
A.
C.
85 kg
50 kg​