12.6 CHAPTER 12. FORCE,MOMENTUM AND IMPULSE
- A 30 kg box sits on aflat frictionless surface.Two forces of 200 N each are applied
to the box as shown inthe diagram. Which statement best describes the motion of
the box?
(a) The box is lifted offthe surface.
(b) The box moves to the right.
(c) The box does not move.
(d) The box moves to the left.
30kg
30 ◦
200N
200N
- A concrete block weighing 200 N is at rest on an inclined surface atan angle of 20◦.
The normal reaction, innewtons, is
(a) 200
(b) 200 cos 20◦
(c) 200 sin 20◦
(d) 2000 cos 20◦
- [SC 2003/11]A box,mass m, is at rest on a roughhorizontal surface. A force of
constant magnitude F is then applied on the box at an angle of 60◦to the horizontal,
as shown.
F
A B
m
60 ◦
rough surface
If the box has a uniformhorizontal accelerationof magnitude, a, the frictional force
acting on the box is...
(a) F cos60◦− ma in the direction of A
(b) F cos60◦− ma in the direction of B
(c) F sin60◦− ma in the direction of A
(d) F sin60◦− ma in the direction of B
- [SC 2002/11 SG] Thabo stands in a train carriage which is movingeastwards. The
train suddenly brakes. Thabo continues to moveeastwards due to the effect of:
(a) his inertia.
(b) the inertia of the train.
(c) the braking force onhim.
(d) a resultant force acting on him.
- [SC 2002/11 HG1] Abody slides down a frictionless inclined plane.Which one of
the following physical quantities will remain constant throughout the motion?
(a) velocity
(b) momentum
(c) acceleration
(d) kinetic energy
