Problems Velocity & Acceleration

Physical Science

1. A car’s velocity changes from 0 m/sec to 30 m/sec 10 seconds later. Calculate the

car’s average acceleration.

a = velocity final – velocity initial

time

a= 30 m/sec - 0 m/sec

10 seconds

a = 3 m/sec2

2. A roller coaster starts down a hill at 10 m/sec. Three seconds later, speed increased to 32 m/sec. What is the

acceleration?a = velocity final – velocity initial

time

a = 32m/sec – 0 m/sec

3 sec

a = 10.7 m/2

3. A swimmer speeds up from 1.1 m/sec to 1.3 m/sec during the last 20 seconds. What

was the acceleration?

a = velocity final – velocity initialtime

a= 1.3 m/sec – 1.1 m/sec 20 sec

a = 0.01 m/sec2

4. A satellite has an initial velocity of 10,000 m/sec. After a minute it is 5000 m/sec.

What is the satellite’s acceleration?

a = velocity final – velocity initialtime

a = 5000 m/sec – 10,000 m/sec60 sec

a = - 83.3 m/sec2

Speed and Acc Ch 3 # 1 A car traveled 1025 km from El Paso to Dallas in 13.5 hrs.

What was the average velocity?

Vave = distance

time

Vave = 1025 km

13.5 hrs

Vave = 75.9 km/hour

2. A car traveling north with a velocity of 30 m/sec slows down to a velocity of 10 m/s within 10

seconds. What is the car’s acceleration?

a = velocity final – velocity initialtime

a = 10 m/sec – 30 m/sec = -20 m/sec 10 sec 10 sec

a = -2 m/sec/sec or 2 m/sec2

3. If the average speed of a car is 45 km/hr, how far can it travel in 40 min?

Vave = distance distance = Vave X time

time

distance = 45 km/hr X 40/60 minute

distance = 30 km

4. Falling objects drop with an average acc of 9.8 m/sec/sec. If an object falls from a tall building, how long will it take before it reaches a speed of

49 m/sec?

a = velocity final – velocity initial

time

time = velocity final – velocity initial

a

time = 49 m/sec – 0 m/sec

9.8 m/sec2

Time = 5 seconds