Here in this case we can use work energy theorem
As per work energy theorem
Work done by all forces = Change in kinetic Energy of the object
Total kinetic energy of the solid sphere is ZERO initially as it is given at rest.
Final total kinetic energy is sum of rotational kinetic energy and translational kinetic energy

also we know that


Now kinetic energy is given by





Now by work energy theorem
Work done = 10500 - 0 = 10500 J
So in the above case work done on sphere is 10500 J
In order to find the force (F), you would have to use the formula for it:
F=ma
where m is mass and a is acceleration.
In the problem, the mass is 2.85kg and the acceleration is 4.9m/s^2.
Therefore,
F=2.85kg(4.9m/s^2)
F=13.965kg(m/s^2)
Since N=kg(m/s^2)
F=13.965N
And because the problem requires that we use only 2 significant figures,
F=13N
Therefore, the student must exert 13N of force.
Answer:

Explanation:
Given that
x= 150 ft

y= 14 ft
From the diagram

When ,x= 150 ft and y= 14 ft


z=150.74 ft

By differentiating with respect to time t


Here x is constant that is why


Now by putting the values in the above equation we get



Therefore the distance between balloon and observer increasing with 0.65 ft/s.
<span>This problem can be solved by the formula used to find resistance. The formula is R=V/I which basically means divide the Voltage by the Current to find the Resistance in an object. Ohm's law.</span>