Force and Motion 8.6B, 6.8A/C/D

(6.8C) A student walks 2 km in 30 minutes.   What is the student's average speed in km/h?

• 4
• 0
• +

(8.6B) What is the difference between the velocity and the speed of an object?

• Velocity is the change in distance over time, while speed is the change in velocity over time. 
• Velocity has a direction associated with it, while speed has no specific direction.
• Velocity has no direction associated with it , while speed has a specific direction. 
• Velocity is the change in speed over time, while speed is the change in distance over time. 

(6.8D)

• A student walks 1.5 km to a friend's house in 40 minute.  the two studetns then walk another 1.5 km to school in 20 minutes. 
• A student walks 1.5 km to a friend's house in 20 minutes.  The two students then walk another 1.5 km to school in 40 minutes.
• A student walk 1.5 km to a friend's house in 30 minutes.  The two students then walk another 1.5 km to school in 30 minutes. 
• A student walks 1.5 km to a a friend's house in 20 minutes.  The two students then walk another 1.5 km to school in 60 minutes. 

(8.6B) The three vehicles shown below are all traveling at a speed of 15 m/s, but only the pickup truck has a changing velocity.
The pickup truck has a changing velocity because the pickup truck--

• can accelerate faster than the other two vehicles
• is traveling in the opposite direction from the other two vehicles
• is traveling on a curve in the road
• needs a large amount of force to move

(6.8A) At which of these positions does the ball have both the greatest kinetic energy and the least potential energy?

• Position 1
• Position 2
• Position 3
• Position 4