Answer:
Explanation:
Given
Minute hand length =16 cm
Time at a quarter after the hour to half past i.e. 1 hr 45 min
Angle covered by minute hand in 1 hr is 360 and in 45 minutes 270
(c)For the next half hour
Effectively it has covered 2 revolution and a quarter
angle turned 
(f)Hour after that
After an hour it again comes back to its original position thus displacement is same =25.136
Angle turned will also be same i.e. 
Explanation:
Work done is the force applied to move a body through a specific or particular direction.
It is also the difference in the amount of energy expended in using an effort.
Work done is given as;
Work done = F x d CosФ
F is the force applied
d is the displacement
Ф is the angle
The unit of work done is in Joules.
Answer:
b) there must be a component of force parallel to the motion of the object.
Explanation:
We know that work done on a body by an external force is calculated by the formula given below:
W = F.d = Fd Cos θ
where,
W = Work Done by the force on the body
F = Magnitude of force
d = displacement of the body
θ = The angle between the direction of motion of the body and the force applied
It is clear from the formula of the work done, that "F Cosθ" represents the component of the force, that is acting in the direction of motion of the object or parallel to the direction of motion of the object. So, if there is no component of force parallel to motion of object, then this factor will become zero. As a result, the work done will also be zero.
Therefore, the correct option will be:
b) <u>there must be a component of force parallel to the motion of object.</u>
The formula for<span> </span>mechanical advantage<span> (MA) for levers: You can use the ratio of the input arm length to the output arm length (input/output): Most of the time, levers are used to multiply force to lift heavy objects.</span>
