Answer:
1 B. Convert v from km/min to m/s ( show work and units
The horizontal velocity<span> of a projectile is </span>constant<span> (a never </span>changing<span> in value), There is a </span>vertical<span>acceleration caused by gravity; its value is 9.8 m/s/s, down, The </span>vertical velocity<span> of a projectile </span>changes<span> by 9.8 m/s each second, The </span>horizontal<span> motion of a projectile is independent of its </span>vertical<span> motion.</span>
The energy bar eaten by Sheila has chemical energy locked up inside it. This chemical energy is converted to mechanical energy in form of potential and kinetic energy and this in turn is converted to heat energy as the run progresses. Thus, the energy changes are: chemical energy to mechanical energy [kinetic and potential] and finally to heat energy.
Energy cannot be created nor be destroyed
<h3>
Answer:</h3>
20 seconds
<h3>
Explanation:</h3>
<u>We are given</u>;
- Power of the engine as 400 watts
- Force as 100 N
- Distance the object is lifted up as 80 m
We are required to determine the time taken.
- We need to know that power is the rate of work done
Therefore;
But, work done = Force × distance
Work done = 100 N × 80 m
= 8000 Joules
- Since , Power = Work done ÷ time
Then, time = Work done ÷ Power
Thus;
Time = 8000 J ÷ 400 W
= 20 s
Therefore, the time taken by the engine to lift the object is 20 seconds
