Question

A body of mass 5 kg is suspended by a spring balance on an inclined plane as shown in figure. The spring balance measure

A. 50 N
B. 25 N
C. 500 N
D. 10 N

Answer 1

Hint: In order to deal with this question first we will calculate the acceleration of the body. Then we will proceed further by using the formula of force. This question can be solved by first checking for all the forces that the body experiences due to various factors present.

Formula used- $F = m \times a$

Complete Step-by-Step solution:
As we know that spring balance will measure the force applied on it, so let us calculate the force applied on the spring balance.
Given that mass of the given body is = 5 kg
As we know that
Acceleration of the body down the rough inclined plane $ = g\sin \theta $
Force applied on spring balance
$F = m \times a$
Substitute the values of mass and acceleration we get
$
  \because F = m \times a \\
   \Rightarrow F = m \times g\sin \theta \\
   \Rightarrow F = 5 \times 10\sin {30^0} \\
   \Rightarrow F = 5 \times 10 \times \dfrac{1}{2}{\text{ }}\left[ {\because \sin {{30}^0} = \dfrac{1}{2}} \right] \\
   \Rightarrow F = 25N \\
 $
Therefore, Force applied on spring is 25N
Hence, the spring balance measures 25 N.
So, the correct answer is option B.

Note- In such types of problems of inclined surfaces as we know that the acceleration due to gravity acts in vertically downward direction, so first we will find the acceleration on the surface which is inclined with the help of trigonometric tools and then we will proceed further. The weight of any given object can be referred to as the force acting on the given object due to force of gravity. Spring balance in such problems just doesn't measure weight, rather it measures the force applied on it.