Problem involving deceleration with a constant. Please help!

[thomcart8]

A car is going 80 feet per second and the driver puts on the brakes, bringing the car to a stop in 5 seconds. Assume the deceleration of the car is constant while the brakes are on.

Ok, I am asked to find what the deceleration of the car is in m/sec^2 and how far the car travels from the time the brakes are applied until it stops.

Ok if it is going 80 ft per 5 seconds it is actually going 16 ft per second. After that I am not really sure where to go with this or even if i am starting in the right way. Can I please get some help?

 

[Deleted member 4993]

Re: Problem involving deceleration with a constant. Please h

A car is going 80 feet per second and the driver puts on the brakes, bringing the car to a stop in 5 seconds. Assume the deceleration of the car is constant while the brakes are on.

Ok, I am asked to find what the deceleration of the car is in m/sec^2 and how far the car travels from the time the brakes are applied until it stops.

Ok if it is going 80 ft per 5 seconds it is actually going 16 ft per second. After that I am not really sure where to go with this or even if i am starting in the right way. Can I please get some help?

No

it is going 80 ft/sec initially

Final velocity is 0 ft/sec.

First find the deceleration using Galileo's first equation

v = u + at

where:

v = final velocity

u = initial velocity

t = elapsed time

a = acceleration (or deceleration)

Then use Galileo's third equation

v[sup:3v18v7v4]2[/sup:3v18v7v4] = u[sup:3v18v7v4]2[/sup:3v18v7v4] + 2as

v = final velocity

u = initial velocity

s = distance travelled

a = acceleration (or deceleration)