Question

question 21 of 29
after manufacturers make a car model, they sometimes try to redesign the car to make it lighter. according to newtons 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 more force exerted on it by earth.
c. the redesigned car will have tires with greater friction force.
d. the redesigned car will accelerate more quickly

Explanation:

Newton's second - law is $F = ma$ (where $F$ is force, $m$ is mass, and $a$ is acceleration). If the car is made lighter (mass $m$ decreases) and the force $F$ remains the same (since nothing else changes), from the formula $a=\frac{F}{m}$, the acceleration $a$ will increase. Inertia is related to mass, so a lighter car has less inertia. The force exerted by Earth (weight) $W = mg$ decreases with mass. There is no indication that tire - friction changes just because the car is made lighter.

Answer:

D. The redesigned car will accelerate more quickly