Answer:v=2 m/s
Explanation:
Given
Length of string L=1.2 m
mass of pendulum m=0.25 kg
maximum inclination with vertical \theta =34
vertical Rise of Pendulum from its mean position is given by

Conserving Energy at top and bottom point
Potential Energy of sphere is converted into kinetic energy of sphere





For Newton's second law, the resultant of the forces acting on the book is equal to the product between the mass of the book and its acceleration:

(1)
There are only two forces acting on the book:
- its weight, directed downward: mg
- the force exerted by the hand on the book, of 20 N, directed upward
so, equation (1) becomes

from which we can calculate the book's acceleration, a:
Answer:
The change in gravitational potential energy of the hiker = 2869685 J
Explanation:
Potential Energy: This is the energy possessed by a body, due to its change in position in the gravitational field. The unit of potential energy is Joules (J)
From the question,
Change in gravitational potential energy = Energy of the hiker at the top of Mt. Whitney - Energy of the hiker at the floor of Death valley.
ΔEp = mgh₂ - mgh₁
ΔEp = mg(h₂-h₁)........................... Equation 1
Where ΔEp = change in Potential Energy of the hiker, m = mass of the hiker, g = acceleration due to gravity, h₁ = lowest point in Death valley, h₂ = Elevation of Mt. Whitney.
Given: m = 65.0 kg, h₁ = -85 m ( because is a valley), h₂ = 4420 m,
Constant: g = 9.8 m/s²
Note: The h₁ is negative because is below sea level.
Substituting into equation 1
ΔEp = 65×9.8×[4420-(-85)]
ΔEp = 637(4420+85)
ΔEp = 637(4505)
ΔEp = 2869685
ΔEp = 2869685 J.
Thus the change in gravitational potential energy of the hiker = 2869685 J
Answer:
So length of pendulum is 143.129 m
Explanation:
We have given period of simple pendulum is 2 sec
We have to find the length of simple pendulum
Let the length of pendulum is l
Acceleration due to gravity
is
Time period is given by 
So 

Squaring both side

l =143.129 m
So length of pendulum is 143.129 m
Answer:
12.5 J
Explanation:
Force, F = 25 N
Distance, d = 0.5 m
The direction of force and the displacement is same.
Work is defined as the product of force in the direction of displacement and the displacement.
Work = Force x displacement x CosФ
Where, Ф be the angle between force and the displacement
Here, Ф = 0°
So, W = 25 x 0.5 x Cos0°
W = 12.5 J