Question

Assume you are driving in a car with a total mass of m = 1250 kg at vi = 20 m/s. You see a light turn red half a mile in front of you and take your foot o the gas. If the wind resistance and all frictional forces combine to supply a force of Fnet = 1000 N, what is your speed after 5 s? What is your speed after 30 s?

Answer 1

After 5 sec speed of the car will be 24 m/sec and after 30 sec speed of the car will be 44 m/sec

Step-by-step explanation:

Mass of the car m = 1250 kg

Initial velocity of the car
`v_i=20m/sec`

Net force is given
`F_(net)=1000N`

From newton's law F = ma, here m is mass and a is acceleration

So
`1000=1250* a`

`a=0.8m/sec^2`

From first equation of motion

`v_f=v_i+at`

For t = 5 sec

`v_f=20+0.8* 5=24m/sec`

For t = 30 sec

`v_f=20+0.8* 30=44m/sec`