# Physics

posted by .

Two cars travel westward along a straight highway, one at a constant velocity of 85 km/hr, and the other at a constant velocity of 115 km/hr.

a) Sketch the velocity vs. time graph for both cars and paste your sketch in the space below.

b) Assuming both cars start at the same point, how much sooner does the faster car arrive at a destination 16 km away?

c)How far must the cars travel for the faster car to arrive 15 min before the slower car?

• Physics -

b. d1 = 85t1 = 16 km,
85t1 = 16,
t1 = 16 / 85 = 0.1882 h = 11.29 min.

d2 = 115t2 = 16 km,
115t2 = 16,
t2 = 16 / 115 = 0.139 h = 8.35 min.

t1 - t2 = 11.29 - 8.35 = 2.94 min.
Car #2 arrives 2.94 min. sooner.

c. 15 min = 1/4 h = 0.25 h.
d1 = d2,
115t = 85(t + 0.25),
115t = 85t + 21.25,
115t - 85t = 21.25,
30t = 21.25,
t = 21.25 / 30 = 0.71 h,

d = 115 * 0.71 = 81.65 km.

## Similar Questions

1. ### Physics

A boy is cycling at a constant speed along a straight road to his school. The postions of the boy after fixed time intervals are observed. a. What type of position-time graph can be expected for the motion of the bicycle?
2. ### physics

A small first aid kit is dropped by a rock climber who is descending at a constant velocity of - 1.3m/s. a) Sketch the velocity vs. time graph for both the climber and her first aid kit and paste your sketch in the space below. b) …
3. ### phyics

If two cars are traveling along a straight road, one behind the other. the first is traveling at a constant velocity of 10 m/s. the second, approaching from the rear, is traveling at 22 m/s. when the second car is 300m behind the first, …
4. ### Physics

Two equal mass cars collide head to tail and their bumpers lock. One car has a velocity of 10 m/s and the other is at rest. What is the velocity of the two cars after the collision?
5. ### Physics

A car moves in a circular path at 15 mph. Which of the following statements about the cars motion would be correct?
6. ### physics

Two cars cover the same distance in a straight line. Car A covers the distance at a constant velocity. Car B starts from rest and maintains a constant acceleration. Both cars cover a distance of 487 m in 216 s. Assume that they are …
7. ### physics

Assume a canister in a straight tube moves with a constant acceleration of -3 m/s2 and has a velocity of 13.5 m/s at t = 0.00 s. (a) What is its velocity at t = 1.00 s?
8. ### Physics

Two cars pass each other traveling at the same speed. One car has a constant velocity of 18.0 m/s east. The other car has a constant acceleration of 3.00 m/s^2, west. How much time will have elapsed until the cars are 128 m apart?
9. ### Physics

Two cars cover the same distance in a straight line. Car A covers the distance at a constant velocity. Car B starts from rest and maintains a constant acceleration. Both cars cover a distance of 515 m in 229 s. Assume that they are …