A force F is applied on sn object to displace it through a distance S. For what angle between them, the work done will be (i) maximum (ii) positive (iii) negative (iv)zero ?
Answers
Explanation:
1) W is max when force and displacement will be in same direction.
2) when force and displacement will be in same direction then work done will be positive.
3)when force and displacement will be in opposite directions then work done will be negative.
4) When force and displacement will be perpendicular to each other then work done will be zero.
Answer:
a) When the angle between them is 0°
b) When the angle between them is acute i.e. more than 0° but less than 90°
c) When the angle between them is obtuse i.e. more than 90° but less than 180°
d) When the angle between them is 90°
Explanation:
Work done = Force x Displacement x Cosθ
where θ is the angle between the force and displacement
a) For maximum work done, cosθ must be maximum. So, the maximum value of cosθ is 1 when θ = 0°
b) For positive work done, cosθ must be positive. So, cosθ is positive for all acute angles. (0°<θ<90°)
c) For negative work done, cosθ must be negative. So cosθ is negative for all obtuse angles. (90°<θ<180°)
d) For zero work done, cosθ must be 0. So the value of cosθ is zero when θ = 90°
Hope it helps,
Alvika