Question

draw free body diagram

A boxed cake is placed in the trunk of a car to be delivered to a birthday party. The coefficient of static friction is 0.15 and for kinetic friction is 0.11. What is the minimum 0-60 mph time that the car can accelerate and keep the box from sliding? In other words, what is the shortest time for the driver to accelerate from a stop up to 60 mph and not have the box slide back in the trunk? 7.

Answer 1

GIVEN

Coefficient of static friction = 0.15

Coefficient of dynamic friction = 0.11

Hint:

Only when the box starts to move the coefficient of dynamic friction governs the friction force until the box remain static coefficient of static friction governs the friction force.

In the question it is given that the box should not slide so, coefficient of static friction will govern the friction force in this problem.

Solution

a - acceleration of car

F_{​​​​​​f} - friction force

R_{​​​​​​N} - reaction force

Result

The minimum time in which the car can accelerate from 0 mph to 60 mph is 18.228 seconds.