Page 25 - Physics Form 5 KSSM_Neat

Activity 1.5 Decomposition CHAPTER 1

Aim: To resolve a force into two components for an object moving in a direction not parallel to the
direction of the force Force and Motion II
Instructions:
1. Carry out this activity in pairs.
KEMENTERIAN PENDIDIKAN MALAYSIA
2. Study Figure 1.17 and determine the magnitudes of:
(a) the horizontal component of the pushing force.
(b) the vertical component of the pushing force.
3. Study Figure 1.18 and determine the magnitudes of:
(a) the component of the weight of the boy in the direction parallel to the inclined plane.
(b) the component of the weight of the boy in the direction perpendicular to the inclined plane.

60°
Pushing force,
Weight of the boy,
F = 32 N
W = 300 N
50°

Figure 1.17 Mopping the floor Figure 1.18 Going down the slide
Discussion:
1. What is the purpose of resolving a force into two perpendicular components?
2. Discuss the suitability of resolving a force into two components that are not perpendicular.

Solving Problems Involving Resultant Force and LET’S ANSWER
LET’S ANSWER
Resolution of Forces

Example 1
Figure 1.19 shows a wooden block being pulled by force, T that inclines at an
angle of 30° above the horizontal surface. Table 1.5 shows the magnitudes of http://bit.ly/
the forces acting on the block. 36yhJWl
R T Table 1.5
Wooden
block Force Magnitude
30°
F Pull, T 36 N
R
Weight, W 24 N
Normal reaction, R 6 N
W
Frictional force, F 20 N
Figure 1.19 R
(a) Calculate the magnitudes of the horizontal component and vertical component of the pull, T.
(b) Determine the magnitude and direction of the resultant force acting on the block.
(c) What is the acceleration of the block if its mass is 2.4 kg?

LS 1.2.1 1.2.2 15