(iv)A car weighing 500 kg working against a resistance of 500 N, accelerates from rest to 20m/s in 100 m. The work done by the engine is:- (a) 1.0 X 10^5 (b) 1.5 X 10^5 (c) 1.05 X 10^5 (d) Data is insufficient
Answers
Answer :
The correct answer is option b
The work done by the Engine is 1.5 × 10⁵ J
Step-by-step Explanation :
Given : Mass of Car = 500 kg
Resistance force = 500 N
Initial velocity = 0
Final velocity = 20 m/s
Distance covered = 100m
To find : Work done by the Engine = ?
Using third equation of motion,
v² - u² = 2as
a = v² - u² / 2s
a = (20)² - 0 / 2 × 100
a = 2 m/s²
As f1 = 500 x 2 = 1000 N and f2 (force of friction) = 500 N,
Total force exerted by the engine, F = f1 + f2 = = 1500 N
Work done, W = Fs
= 1500N x 100m
= 150000 J
= 1.5 x 10⁵ J