2.according to newton’s first law, if no force acts on an object, it will just continue moving. explain in terms of newton’s first law why a car engine must exert a force between the car and the road to drive at a constant speed on a straight and level road.

The answer

According to Newton’s first law, if no force acts on an object, it will just continue moving in a straight line with a constant speed or at rest
that means that the sum of all acting forces equals 0

so the car must
exert a force between the car and the road to drive at a constant speed on a straight and level road because the both forces must be balances for making it to move with a constant speed in a straight line.

45 is the correct answer

At maximum height, kinetic energy is converted in potential energy  formula: at max height, ke = ½ * 0.27kg * (16m/s) ² = 34.56 j  so the remaining pe = (41.70 – 34.56)= 7.14 j = 0.27 kg * 9.8m/s² * h  = (9.8/7.14 * 0.27)so max height h = 5.08 or 5 m