Work by constant and variable force
- A force F = 20 + 10y acts on a particle in y-direction where F is in newton and y in meter. Work done by this force to move the particle from y = 0 to y = 1 m is : Answer: 3. 25 J Work done by a variable force is W=∫ F dy . W=∫₀¹(20+10y) dy=[20y+5y²]₀¹=20+5=25 J. 1
- A particle moves from a point (-2 i+5 j) to (4 j+3 k) when a force of (4 i+3 j) N is applied. How much work has been done by the force? Answer: 2. 5 J Work =vec F·vec d , where vec d is the displacement. vec d=(4hat j+3hat k)-(-2hat i+5hat j)=2hat i-hat j+3hat k . W=(4hat i+3... 1