# Maths

The braking distance of a car is directly proportional to te square of it's speed.
When the speed is p metres per second, the braking distance is 6m. When the speed is increased by 300%, find
(a) an expression for speed of the car
(b) the braking distance
(c) the % increase in the braking distance

Is there any fixed methods for this type of question? Thanks a lot!!! :)))))))

1. 👍
2. 👎
3. 👁
1. d = k v^2 so v = sqrt(d/k)

6 = k p^2 so p = sqrt (6/k)

new speed = 4 p = 4 sqrt (6/k)

new d = k v^2 = k*16(6/k) = 96 meters

96/6 = 16 times = 1600 %
or
new speed = 1600 percent of old speed
so
percent increase = 1600-100 = 1500% increase

1. 👍
2. 👎
2. How did you find new speed?

1. 👍
2. 👎

## Similar Questions

1. ### Physics

You are driving down the highway late one night at 20 m/s when a deer steps onto the road 35 m in front of you. Your reaction time before stepping on the brakes is 0.50 s , and the maximum deceleration of your car is 10 m/s2 . How

2. ### Science

A car is travelling along a straight road. The driver suddenly observes that the road ahead is flooded and applies the brakes. Describe what happens to the car and the brakes. Your answer should include details of braking distance

3. ### physics

You testify as an expert witness in a case involving an accident in which car A slid into the rear of car B, which was stopped at a red light along a road headed down a hill (see the figure). You find that the slope of the hill is

4. ### Math

the stopping distance of an automobile is directly proportional to the square of its speed v. a car required 90 feet to stop when its speed was 70 miles per hour. find a mathematical model that gives the stopping distance d in

1. ### Physics answer check pls

1. The electrostatic force between two charges is originally F. Which expression represents the new electrostatic force between the two charges if one charge doubles and the other one is divided by three? A. 3/2 F B. 2/3 F C. 1/6

2. ### math

The stopping distance d of a car after the brakes have been applied varies directly as the square of the speed r. If a car traveling 40 mph can stop in 100 ​ft, how fast can a car travel and still stop in 256 ​ft?

3. ### math

The stopping distance (s) of a car varies directly as the square of its speed (v). If a car traveling at 50 mph requires 170 ft to stop, find the stopping distance for a car traveling at v2 = 55 mph.

4. ### Physics

I need help on this question: You are given information on the intensity level (which is a measure of the sound intensity) at a point and its distance from the sound source. To make use of this information, you will need to

1. ### Physics

You are driving down the highway late one night at 20 m/s when a deer steps onto the road 35 m in front of you. Your reaction time before stepping on the brakes is 0.50 s , and the maximum deceleration of your car is 10 m/s2 . How

2. ### physics

A car starts from rest and travels for t1 seconds with a uniform acceleration a1. The driver then applies the brakes, causing a uniform acceleration a2. If the brakes are applied for t2 seconds, determine the following. Answers

3. ### Physics

A driver in a car, originally moving at 13.1 m/s, applies the brakes until the car comes to a stop. The car moves a distance of 34.1 m while braking. How much time did it take for the car to stop? Assume constant acceleration

4. ### Physics

To stop a car, you require first a certain reaction time to begin braking. Then the car slows under the constant braking deceleration. Suppose that the total distance moved by your car during these two phases is 56.7 m when its