Kinetic energy = mass time squared speed divided by 2
W=mv^2/2 = 50*10*10/2 = 2500 J
Answer:
t = 6.17 s
Explanation:
For a 1 revolution movement, 
Torque, 
Moment of Inertia, 
If the wheel starts from rest, 
The angular displacement of the wheel can be given by the formula:
................(1)
Where
is the angular acceleration

To get t, put all necessary parameters into equation (1)

Answer:
55407
Explanation:
we have given that magnetic field B=3.5 T
current through the coil=90 A
Length of solenoid =0.72 m
we know the formula of magnetic field

so 
so the number of turn in solenoid will be 55407
Answer:
50.3N
Explanation:
Work done = force x distance
422J. = force x 8.39m
÷8.39 both side to get force
Force is 50.3N to 1 d.p.
Check:
50.3 x 8.39=422.017J
Same as 422J to 1 d.p