1. Differentiate between speed and velocity.

2. Using examples to describe each term, differentiate among average, instantaneous, and uniform velocity.

Solve each problem.

3. A driver of a car hits its brakes and begins to decelerate. If the velocity changes from 60 m/s to 20 m/s in 6 s, what is the deceleration of the car?

4. A researcher observes a vehicle with an initial velocity of 14 m/s. The vehicle accelerates uniformly with an acceleration of 3 m/s2. After 6 seconds, what is the velocity of the vehicle?

5. It takes you 5 hours to complete a 375-kilometer trip. What was your average speed on this trip?

6. Henry takes a boat ride for 15 minutes to reach his destination. If the boat was traveling at 6 meters/second, how far did the boat travel?

7. A storm is moving east towards your house at an average speed of 35 km/hr. If the storm is currently 80 kilometers from your house, in how much time do you expect it to arrive?

8. If the velocity of an object changes from 15 m/s to 50 m/s during a time interval of 4 s, what is the acceleration of the object?

9. If the acceleration in question 8 is constant, what's the average velocity of the object described?

10. A van is traveling at 11.5 m/s. To avoid hitting a deer, the brakes are applied, and the van stops within 3.5 seconds. What is the acceleration?

1. Speed and velocity both involve a numeric rate describing the distance traveled by a body in a unit of time. However, speed describes the rate of a body traveling in any direction in a unit of time, while velocity describes the rate of a body traveling in a particular direction in a unit of time.

2. Answers may vary, but should resemble the following:

Average velocity explains the velocity the body traveled overall, not taking into consideration each spot in the trip. If a car moves at 65 km/h on average, it may have slowed down for some parts and sped up for others. Overall though, it would have made a certain distance of travel within a specified unit of time that totals the average velocity of 65 km/h.

Instantaneous velocity explains the velocity of a body at a particular instant of the trip. The instantaneous velocity of a car stopped at a stop sign would be 0 m/s even if it was moving before and will continue to move after this stop. The velocity at that particular instant is the instantaneous velocity.

Uniform velocity is when the distance being covered is changing uniformly with time. For example, if a car moves 20 km every 30 minutes and continues to do so in the same direction, it's traveling with a uniform velocity.

3. a=v2−v1t

a=20 m/s−60 m/s6 s

a=−406

a = –6.7 m/s2

4. v2 = v1 + at

v2 = 14 m/s + (3 m/s2 × 6 s)

v2 = 14 + 18

v2 = 32 m/s

5. v=st

v=375 km5 h

v = 75 km/h  

6. First, convert the minutes to seconds. Since there are 60 seconds in one minute, multiply:

60 × 15 (minutes) = 900 seconds

s = v × t

s = 6 m/s × 900 s

s = 5,400 m

7. t=sv

t=80 km35 km/hr

t = 2.29 hr

8. a=v2−v1t

a=50 m/s−15 m/s4 s

a=35 m/s4 s

a = 8.75 m/s2

9. vav=v1+v22

vav=15 m/s+50 m/s2

vav=65 m/s2

vav = 32.5 m/s

10. a=v2−v1t

a=0 m/s−11.5 m/s3.5 s

a = –3.29 m/s2

Explanation:

not moving. pos accel,

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle