Explanation:
power=f×v. recall= distances/ time
= f× d/t
= 30 × 2/5
=12watt
Answer:

Explanation:
An object is at rest along a slope if the net force acting on it is zero. The equation of the forces along the direction parallel to the slope is:
(1)
where
is the component of the weight parallel to the slope, with m being the mass of the object, g the acceleration of gravity,
the angle of the slope
is the frictional force, with
being the coefficient of friction and R the normal reaction of the incline
The equation of the forces along the direction perpendicular to the slope is

where
R is the normal reaction
is the component of the weight perpendicular to the slope
Solving for R,

And substituting into (1)

Re-arranging the equation,

This the condition at which the equilibrium holds: when the tangent of the angle becomes larger than the value of
, the force of friction is no longer able to balance the component of the weight parallel to the slope, and so the object starts sliding down.
Given:
F = ax
where
x = distance by which the rubber band is stretched
a = constant
The work done in stretching the rubber band from x = 0 to x = L is
![W=\int_{0}^{L} Fdx = \int_{0}^{L}ax \, dx = \frac{a}{2} [x^{2} ]_{0}^{L} = \frac{aL^{2}}{2}](https://tex.z-dn.net/?f=W%3D%5Cint_%7B0%7D%5E%7BL%7D%20Fdx%20%3D%20%5Cint_%7B0%7D%5E%7BL%7Dax%20%5C%2C%20dx%20%3D%20%5Cfrac%7Ba%7D%7B2%7D%20%20%5Bx%5E%7B2%7D%20%5D_%7B0%7D%5E%7BL%7D%20%3D%20%20%5Cfrac%7BaL%5E%7B2%7D%7D%7B2%7D%20)
Answer: