# physics

A car starts from rest and travels for 5.0 s with a uniform acceleration of +2.5 m/s2. The driver then applies the brakes, causing a uniform negative acceleration of -3.0 m/s2. If the brakes are applied for 2.0 s, how fast is the car going at the end of the braking period, and how far has it gone?

1. 👍 0
2. 👎 0
3. 👁 1,925
1. V1 = a*t = 2.5 * 5 = 7.5 m/s.

a. V2 = V1 + a*t = 7.5 -(3 * 2) = 1.5 m/s. After the braking period.

b. d1 = 0.5a*t^2 = 0.5*2.5*5^2 = 31.25 m.

d2 = V1*t + 0.5a*t^2.
d2 = 7.5*2 - 0.5*3*2^2 = 9 m.

d = d1+d2 = 31.25 + 9 = 40.25 m.

1. 👍 2
2. 👎 3

## Similar Questions

1. ### physics, dynamics

Car A starts from rest at t = 0 and travels along a straight road with a constant acceleration of 2 m/s2 until it reaches a speed of 27 m/s. Afterwards it maintains this speed. Also, when t = 0, car B located 2000 m down the road

2. ### physics

a car starts from rest , attains a velocity of 36kmph with an acceleration of 0.2m/s^2 travels 9km with this uniform velocity and then comes to halt with a uniform acceleration of 0.1m/s^2 find the total time of travel of the car.

3. ### physics

a particle starts moving from rest with uniform acceleration . it travels a distance y in the next 2 sec

4. ### physics

A test car starts out from rest on a horizontal circular track of 80m radius and increases it's speed at a uniform rate to reach 27.78 m/s in 10s. Find the magnitude of the total acceleration of the car 8s after the start. Ok so I

1. ### physics

A 75 kg man stands on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of 1.6 m/s in 1.1 s. It travels with this constant speed for the next 7.2 s, undergoes a uniform negative

2. ### physics

A car starts from rest and travels for 5.3 s with a uniform acceleration of +1.2 m/s2. The driver then applies the brakes, causing a uniform acceleration of -2.3 m/s2. The breaks are applied for 1.60 s. How fast is the car going

3. ### physics

A racing car reaches a speed of 40 m/s. At this instant, it begins a uniform negative acceleration, using a parachute and a braking system, and comes to rest 5.0 s. (a)Determine the acceleration of the car. Work: 40m/s x 5s = 200m

4. ### Physics

A car starts from rest accelerate uniformly until it reaches a velocity of 30m/s after 5s.it traves with uniform velocity for 15s and is being brought to rest in 10 with a uniform retardation.dEtermine the following (a) the

1. ### physics

A car starts from rest and travels for 6.0 s with a uniform acceleration of +1.2 m/s2. The driver then applies the brakes, causing a uniform acceleration of -1.8 m/s2. The breaks are applied for 1.70 s. (a) How fast is the car

2. ### physics

A car starts from rest and travels for 6.0s with a uniform acceleration of 2.7m/s ^2. The driver then applies the brakes, causing a uniform acceleration of -2.0m/s^2. If the brakes are applied for 2.0s, determine each of the

3. ### physics

A car starts from rest and travels for 4.5 s with a uniform acceleration of +1.8 m/s2. The driver then applies the brakes, causing a uniform acceleration of -1.8 m/s2. The breaks are applied for 1.80 s.

4. ### physics

A car starts from rest and accelerates uniformaly at the rate of 0.98m/s in 1hr.what is its final velocity? A car starts from rest and reaches a velocity of 40m/s in 1minutes..(a)what is its acceleration?(b) If its acceleration