SI Units
What is the SI unit for speed?
m/s
How many millimeters are in 2 km?
2,000,000 mm
Imagine being in a car. The driver suddenly slams down on the breaks and your body continues moving forward before being stopped by the seatbelt. Which law of motion is this?
Newton's 1st law
Why is the efficiency of a machine always less than 100%?
Some work input is lost to friction
What happens to kinetic and potential energy as a ball fall to the ground?
Potential decreases and kinetic increases.
What is the SI unit for distance?
meter
Susie runs 3 miles south, then turns and runs 2 miles north. What is the displacement of her run?
1 mile south
When someone rides a bike and applies the breaks, what is the main thing causing the bike to slow down?
Friction
What two simple machines make up a pair of scissors?
lever and wedge
Friction converts mechanical energy into...
thermal energy
What is the SI unit for velocity?
m/s
An object rolls east at a steady speed of 9m/s for 3 seconds. What distance did it travel?
27 m
What happens to the weight of an astronaut as she travels further away from Earth?
Her weight decreases because gravity decreases.
When you make grooves on a screw closer together, why does the mechanical advantage increase?
The closer threads increase the distance
When you see solar panels on a roof, which form of energy is collected by the panels?
A) sound
B) magnetic
C) kinetic
D) radiant
D) radiant
What is the SI unit for acceleration?
m/s2
How long will it take a car to accelerate from 20 m/s to 26 m/s at a rate of 1.4 m/s2?
4.3s
A heavy football player and a light football player collide. Which player hits the other with more force?
they both hit with equal forces
The rate at which work is done is known as...
Power
What form of energy do batteries store?
Chemical
What is the SI unit for displacement?
meters
If a Ferrari, with an initial velocity of 10 m/s, accelerates at a rate of 50 m/s2 for 3 seconds, what will its final velocity be?
160 m/s
A 100 N force causes an object to accelerate at 2 m/s2. What is the mass of the object?
50kg
It takes a force of 25N to raise the flag up the flagpole. The load is 60N. What is the mechanical advantage?
2.4
What is the law of conservation of energy?
Energy cannot be created or destroyed; only converted from one form to another