Answer:
Explanation:
Given
mass of box 
coefficient of kinetic friction 
coefficient of Static friction 
cart is moving with constant velocity therefore Net Force is zero
Since there is no net acceleration therefore friction force will be zero
mathematically
where 
Velocity of swimmer across river = 1.30 m/s
Distance arrived downstream = 48 m
Width of river = 64 m
Time taken to cross river = 
= 
Speed of river current = 
= 
So, the river is flowing at a speed 0.975 m/s.
<h3><u>Answer;</u></h3>
Kinetic energy
A car engine changes chemical potential energy into the <u>kinetic energy</u> of the moving car.
<h3><u>Explanation;</u></h3>
- A car engine converts potential chemical energy stored in gasoline into thermal energy and then into kinetic mechanical energy.
- When gasoline undergoes combustion it reacts with oxygen to produce carbon dioxide and water vapor.Gasoline is a mixture of octane and similar hydrocarbons and contains potential chemical energy.
- The hot exhaust gases from the combustion of gasoline that are produced within the cylinder expand and exert pressure, moving the piston in the cylinder outward then inward as the gas is exhausted. Kinetic mechanical energy of the moving pistons is transferred to the drive shaft and eventually to the wheels, giving the car kinetic mechanical energy.
Air resistance ------- - - -- - - - :)
