after manufacturers make a car model, they sometimes try to redesign the
car to make it lighter. according to newton's second law of motion, if nothing
else changes, what can be expected to occur?

a. the redesigned car will have more inertia.

b. the redesigned car will have tires with greater friction force.

c. the redesigned car will have more force exerted on it by earth.

d. the redesigned car will accelerate more quickly.

D. The redesigned car will accelerate more quickly.

Explanation:

As nothing else change, the engine remains the same so force of the car remain the same. But as it's mass is lower now, it's acceleration will be higher as mass and acceleration are inversely proportional when the force is constant, as stated by Newton's 2nd law of motion. So D is correct.

A. Inertia will reduce, as mass decrease and the parameters of the car remain the same.

B. The tires will have less frictional force as the weight of the car now reduces, so normal reaction on the floor is also reduced.

C. No increase in force exerted as explained in for B.

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true