CHAPTER 12. FORCE,MOMENTUM AND IMPULSE 12.6
- [SC 2002/11 HG1] Abody moving at a CONSTANT VELOCITY on a horizontal plane,
has a number of unequal forces acting on it. Which one of the followingstatements
is TRUE?
(a) At least two of the forces must be acting in the same direction.
(b) The resultant of theforces is zero.
(c) Friction between thebody and the plane causes a resultant force.
(d) The vector sum of the forces causes a resultant force which acts in the direction
of motion.
- [IEB 2005/11 HG] Two masses of m and 2 m respectively are connected by an elas-
tic band on a frictionless surface. The masses are pulled in opposite directions by
two forces each of magnitude F, stretching the elastic band and holding the masses
stationary.
F
m elastic band 2 m
F
Which of the followinggives the magnitude of the tension in the elasticband?
(a) zero
(b)^12 F
(c) F
(d) 2 F
- [IEB 2005/11 HG] Arocket takes off from itslaunching pad, accelerating up into the
air.
�
F�
W�
tail nozzle
The rocket accelerates because the magnitude of the upward force, F is greater than
the magnitude of the rocket’s weight, W. Which of the following statements best
describes how force F arises?
(a) F is the force of the air acting on the base of the rocket.
(b) F is the force of the rocket’s gas jet pushing down on the air.
(c) F is the force of the rocket’s gas jet pushing down on the ground.
(d) F is the reaction to the force that the rocket exerts on the gases whichescape
out through the tail nozzle.
- [SC 2001/11 HG1]A box of mass 20 kg rests on a smooth horizontal surface. What
will happen to the box if two forces each of magnitude 200 N are applied simultane-
ously to the box as shown in the diagram.
20 kg
200 N^30
◦
200 N
