In case one, a car speeds up from zero m/s to 15 m/s. In case two, the same car speeds up from 15 m/s to 30 m/s. The mass of the car is 1000 kg. Compare the energy needed to provide the increase in speed in each case. Give your answers in joules.

Explanation:

Case 1:

Vo = 0 m/s

V1 = 15 m/s

Case 2:

Vo = 15 m/s

V1 = 30 m/s

Change in KE = 1/2 × m × (V1^2 - Vo^2)

KE1 = 1/2 × 1000 × (15^2 - 0)

= 112.5 kJ

KE2 = 1/2 × 1000 × (30^2 - 15^2)

= 1/2 × 1000 × 675

= 337.5kJ

Case 1 has an increase of 112.5 kJ while Case 2 has an increase of 337.5kJ.

you cant move and you feel like someones pushing you down onto your bed it can feel like you want to get up but you just can't it can be extremely scary

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.