Calculating Speed, Acceleration and Force Review

Calculating Speed Acceleration and Force Review

Speed

The amount of distance an object moves and the amount of time it takes to get there.

 $speed\ =\frac{dis\tan ce}{time}$  

 $s\ =\ \frac{d}{t}$  

Multiple Choice

If a runner measures the distance she runs in kilometers and the time it takes her to run in hours, what units will she use for her speed?

• m/s

• km/h

• mph

• bpm

Multiple Choice

A child riding their bike down the street rides 20 meters in 14 seconds. What is their speed?

• 6 km/h

• 1.4 mph

• 1.4

• 1.4 m/s

Multiple Choice

A hockey puck slides across the ice. It makes it from one side of the rink to the other (60 meters) in 1.36 seconds. How fast was the hockey puck traveling?

• 44 m/s

• 81.6 m/s

• 100 mph

• 0.002 m/s

Multiple Choice

The maglev train in Tokyo is capable of reaching speeds of 620 km/h. At that speed, how much time would it take to get from Fond du Lac to Milwaukee (109 km) ?

• 5.7 hours (5 hours, 42 minutes)

• 0.17 hours (10 minutes)

• 511 hours

• 1.2 hours (1 hour, 12 minutes)

Velocity

The displacement of an object over time. (Speed with a direction)

 $\overrightarrow{v\ }=\frac{\overrightarrow{d\ }}{t\ }$  

Multiple Choice

The weather is nice and sunny so you decide to go on a walk. You walk 4 blocks East in about 3 minutes, 2 blocks North in 1 minute, 3 blocks West in 6 minutes, and 2 blocks South in 20 seconds to end up back at your house. What is your velocity over your whole trip?

• 0

• 1 block per minute

• 11 blocks per minute

• 30 m/s South

Multiple Choice

The marching band marches at a constant velocity of 1.3 m/s North for 45 seconds. What is their displacement?

• 58.5 m/s

• 58.5 m

• 58.5

• 58.5 m North

Acceleration

The change in an object's velocity over time.

 $\overrightarrow{a\ }=\frac{\overrightarrow{v_f}\ -\overrightarrow{v_i}}{t}\$  

 $\overrightarrow{v_f}$  = final velocity
 $\overrightarrow{v_i}$  = initial velocity

Multiple Select

Which controls on your car can you use to cause the car to accelerate? (Check all that apply)

• accelerator pedal

• brake pedal

• steering wheel

• turn signal knob

Multiple Choice

A person on a sled slides down a hill. Near the top of the hill they are moving at 1 m/s and near the bottom of the hill they are moving at 6 m/s. It took them 2.5 seconds to slide down the hill. What was their acceleration?

• 0

• 2 m/s²

• 2.5 m/s²

• 5 m/s²

Multiple Choice

Your friend wants to borrow your calculator, so you slide it across the lab table to them. When it leaves your hand it is moving with a speed of 2 m/s, but by the time it reaches their hand 1 second later it is only moving at a speed of 0.5 m/s. What is the calculator's acceleration?

• -1.5 m/s²

• 1.5 m/s²

• 0.5 m/s²

• 0

Multiple Choice

You push two toy cars and let them go across the floor at about equal speed. The red car comes to a stop in 5 seconds. The blue car comes to a stop after 10 seconds. Which car had a greater acceleration?

• red car

• blue car

• their acceleration was equal

Force

 $F=ma$  

Force = mass x acceleration

Multiple Choice

An object falls. What is its acceleration? (there is no air resistance)

• 9.8 m/s²

• there's not enough information to answer the question

Multiple Choice

A baseball has a mass of 145 g (0.145 kg). How much does it weigh in Newtons?

• 1421 N

• 1.421 N

• 1421 kg/m

• 1.421 lb

Multiple Choice

A baseball falls through the air. The air resistance is 0.2 N. The weight of the baseball is 1.4 N and the mass of the baseball is 0.145 kg. What is the acceleration of the baseball as it falls?

• 9.8 m/s²

• 6.4 m/s²

• 8.3 m/s²

• 12.7 m/s²

Multiple Choice

A rocket accelerates from 0 m/s to 20 m/s in 5 seconds. The net force on the rocket is 8 N. What is the mass of the rocket?

• 25 kg

• 32 kg

• 2.0 kg

• 1.4 kg