A driverless car collides head on with a stationary sign. The collision brings the car to a stop, but does not move the sign. Which design feature would have minimized the force of impact in the collision?

A. a car that can carry a greater mass of passengers and cargo

B. a sign that breaks loose from the ground when a force is applied to it

C. a sign that can withstand the force of a more massive car without moving

D. a car that can decelerate at a greater rate during collisions by not bending on impact

specific latent heat of fusion, lf, of a substance is defined as the amount of heat required to change a unit mass of the substance from solid to liquid state, without any change in the temperature.

explanation:

multiple

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.