Answer:
option (E) is correct.
Explanation:
Work done is defined as the product of force and the distance in the direction of force.
force, f = 100 N
Coefficient of friction, = 0.25
distance = 15 m
So, net force F = f - friction force
F = 100 - 0.25 x m g
Work = (100 - 0.25 mg) x d cosθ
For minimum work, the angle should be maximum.
So, the value of θ is 76°.
thus, option (E) is correct.
Answer:
Explanation:
Potential energy is the energy of a body due to is virtue of rest.
Potential energy is given as mgh
g is a constant and it is 9.81m/s²
And also the mass of the body is given as 1.3kg
Now the height of the body is
He took a book to a storey building of height 26m
He still holds the book 151 cm (1.51m) above the house.
The house is on an altitude of 1609m from the sea level.
Total Ug with out the sea level is
Ug=mgh
Ug=1.3 × 9.81 ×(26+1.51)
Ug=350.84J
Then, the potential energy due to the sea level is given as
Ug=mgh
Where g = 1/6371 m/s²
Therefore
Ug=mgh
Ug=1.3 × 1/6371 ×1609
Ug=0.328J
Total energy = 0.328+350.84
Ug=351.17J
Answer:
0.087 m
Explanation:
Length of the rod, L = 1.5 m
Let the mass of the rod is m and d is the distance between the pivot point and the centre of mass.
time period, T = 3 s
the formula for the time period of the pendulum is given by
.... (1)
where, I is the moment of inertia of the rod about the pivot point and g is the acceleration due to gravity.
Moment of inertia of the rod about the centre of mass, Ic = mL²/12
By using the parallel axis theorem, the moment of inertia of the rod about the pivot is
I = Ic + md²
Substituting the values in equation (1)
12d² -26.84 d + 2.25 = 0
d = 2.15 m , 0.087 m
d cannot be more than L/2, so the value of d is 0.087 m.
Thus, the distance between the pivot and the centre of mass of the rod is 0.087 m.
