I want question no. 6 and 7 and their subquestion full
Pls send fast
1. When θ is acute (<90), cosθ is positive. Hence work done is positive.
example: when a body falls freely under the action of gravity.
cos0 = 1. therefore work done by the gravity on the body falling freely is +ve.
2. When θ is acute (>90), cosθ is -ve. Hence work done is -ve.
example: when a body is thrown up, its motion is opposed by the gravity. the angle θ b/w gravitational force and displacement is 180. cos 180 = -1, therefore work done by the gravity on a body moving upward is -ve.
when, θ = 90
cos90 = 0
work done is said to be zero.
example: when a body tied to one end of a string is rotating in a circle, work done by the centripetal force applied along the string is zero because
θ = 90
cos90 = 0
2) let mass of light body be 'm' & heavy body be 'M'
given that mV=Mv
We know that K E=p2 /2m
since as p is constant K E is inversly proportional to the mass of the object
hence light body has greater kinetic energy
Hope this information will clear your doubts about topic.
For more queries just ask in a separate thread here on the forum and our experts will try to help you out as soon as possible.