Question

300 J of work is done in sounding 2 kg block up an inclined plane of height 10m . The work done against friction is:(take g=10m/S2)

Answer 1

Solution :

Given,

Workdone, W = 300J

Mass, m = 2kg

For finding weight,

w = Mass × Acceleration due to gravity

w = 2 × 10

w = 20N

Height, H = 10 m

For finding the value of work done when friction is involved.

Total Workdone = Workdone against friction(W1) + Workdone against gravity(W2).

Total Workdone = W1 + W2

=> W = W1 + W2

=> W = W1 + (w × h)

[°.° W = F × s]

where, F = w and h = s.

Here,

h means distance or displacement.

w means force or weight.

=> W = W1 + (20 × 10)

=> W = W1 + 200

=> W1 = 300 - 200

=> W1 = 100

.°. W1 = 100J

Thus, the work done against friction is 100J.

Answer: W1 = 100J