Question

*
4. A force of 15 N is required to pull up a body of
mass 2 kg through a distance 5 m along an
inclined plane making an angle of 30° with the
horizontal as shown in Fig. 2.11. Calculate :
(i) the work done by the force in pulling the
body,
(ii) the force due to gravity on the body,
(iii) the work done against the force due to gravity.
Take : g = 9.8 m s-2.
(iv) Account for the difference in answers of
part (i) and part (iii).​

Answer 1

Answer:

Step-by-step explanation:

F = 15 N  

m = 2 kg

g = 9.8 m/s2

s = 5 m  

 

1. Work done by the force in pulling the body,  

 

W = F × s

W = 15 N × 5 m = 75 J  

 

2. Force due to gravity on the body,

 

F = m × g  

F = 2 × 9.8 = 19.6 N  

 

3. Work done against the force due to gravity,  

 

W = Fs cosΘ

W = 19.6 × 5 × cos 30°

W = 49 J  

 

Now as the body is pulled along an inclined plane making an angle of 30° the work done on the body will be less than the work done on the body while pulling it vertically upward.  

Answered by Shiwani Sawant | 11th Feb, 2019,  11:00: AM