3. if a car accelerates from rest at a constant 5.5 m/s, how long will it take for the car to reach a
velocity of 28 m/s?

2.54 s

Explanation:

If we are talking about a constant acceleration, we can use the following equation:

Where:

is the final velocity of the car

is the finitial velocity of the car (it started from rest)

is the constant acceleration of the car

is the time it takes to reach with the given constant velocity

Hence:

Clearing :

Finally:

given data:

determine the horse power (h.p) = ?

force applied to move the box(f) = 10 pounds,

box lifted from a distance         (d) = 3 feet

time taken to lift                         (t) = 10 sec,

the horse power is defined as amount of work required to move a load. the horse power is equal to 550 foot-pound per second

                  1 h.p   = 550 foot-pound/second

it can also be defined as the the load that need to be move a body for certain distance in a certain amount of time.

mathematically,

                      h.p = (force × distance)/ time

                            = (10 × 3)/ 10

                            = 30/10

                            = 3 foot -pound/sec

hence, the horse power is needed to move the box is 3 foot-pound/second

important note: 1 h.p = 550 foot-pound/second = 746 watts