# physics 1

In coming to a stop a car leaves skid marks 92m long on the highway. Assuming a decceleration of 7.00m/s^2, estimate the speed of the car just before braking.

1. 👍 1
2. 👎 3
3. 👁 4,149
1. d = 0.5 * a * t^2,
92 m = 0.5 * 7.0 m/s^2 t^2,
92 = 3.5t^2,
t^2 = 92/3.5 = 26.29,
t = sqrt(26.29) = 5.13 s.

a = (Vt - Vo) / t,
-7.00 m/s^2 = (0 - Vo) / 5.13 s,
-7.00 = -Vo /5.13,
-Vo = - 7.0 * 5.13 = -35.91,
Vo = 35.91 m/s. = velocity Just before braking.

1. 👍 9
2. 👎 4
2. fy

1. 👍 0
2. 👎 2

## Similar Questions

1. ### Physics 1

A 1400 kg car traveling at a speed of 34 m/s skids to a halt on wet concrete where μk = 0.50. How long are the skid marks?

2. ### Physics Part A HELP!!

4.) In coming to a stop, a car leaves skid marks 80m long on the highway. Assuming a DEceleration of 7.00 m/s^2 (m/s/s), estimate the speed of the car just before breaking. 6.) A car traveling @ 90km/h strikes a tree. The front

3. ### Physics

A 1500kg car skids to a halt on a wet road where μk= 0.53. How fast was the car traveling if it leaves 62-m-long skid marks?

4. ### physics

a)Two cars are traveling along a straight line in the same direction, the lead car at 24.5m/s and the other car at 29.6m/s. At the moment the cars are 41.6m apart, the lead driver applies the brakes, causing her car to have an

1. ### Math

The police can determine the speed a car was traveling from the length of the skid marks it leaves. The function they use is S = f(L) = 2sqrt(5L) where S is speed (mph) and L is the length of the skid marks (feet) (a) If skid

2. ### physics

A car moving at 15 m/s skids to a stop after 20 m. How far will it skid if it is moving at 45 m/s, assuming that the braking force is constant?

3. ### Physics

A car will skid to a halt at a uniform rate of -9.4 m/s^2. If you measure skid marks that are 34 m long, with what speed was the car going just before the driver slammed the brakes?

4. ### math

A car skids to a stop, leaving four skid marks with an average length (D) of 60 feet. The road is asphalt. Skid tests reveal a drag factor(f) of 0.75. Since all four wheels were braking, the braking efficiency (n) is 100% or 1.00.

1. ### Algebra

The formula r =2 sqrt.5L can be used to approximate the speed r, in miles per hour, of a car that has left skid marks of length L, in feet. How far will a car skid at 60 mph?

2. ### Physics

Police find skid marks 60 m long on a road showing where a car made an emergency stop. Assuming that the deceleration was -10m/s2, how fast was the car going?

3. ### Zeeland WEST

In a car accidnet involving a sports car, skid marks as long as 290 m were left by the car as it decelearted to a complete stop. The police report cited the speed of the car before breaking as beeing in excess of 100mph 161 km/m.

4. ### Algebra 2

The Formula s= sqrt 30fd can be estimated the speed of s, in miles per hour that a car is traveling when it goes into a skid, where f is the coefficient of friction and d is the length of the skid marks in feet. Kody skids to a