Forces & Motions
A car is is driving faster and faster. What is the name of this change in velocity?
Name the three magnetic elements
iron, cobalt, nickel
What is this called when two variables change in the same way, appearing to be linked
correlation
A car travels a total distance of 280 km in 4 h. What is its average speed?
70 km/h
What is holding you down right now?
Force of gravity
Name two things a force can do to an object
Change speed
Change direction
Change shape
An electromagnet suddenly stops working; what is the most likely thing that happened?
The current was switched off
A graph is a straight line but does not pass through the origin.
Is it directly proportional?
No
A golden retriever has a mass of 30 kg on Earth (g = 9.8 m.s2). What is its weight?
294 N
You are designing the world's slowest race car. Should you increase or decrease drag?
Increase drag
A falling object reaches a point where gravity and drag are equal. What is the name for the speed it has reached?
Terminal velocity
What are three ways that can make an electromagnet stronger?
Increase current
Add more coils
Add a magnetic core
What is a scale model?
An accurately resized copy of something real
A bulb has a voltage of 24 V and a current of 3 A. What is its resistance?
8 Ω
A scientist invents a machine that produces 100 J of energy from nothing. Which scientific law have they broken?
Law of Conservation of Energy
What is work?
Work is energy transferred when a force moves an object
What happens to total current in each branch of a parallel circuit?
It divides between the branches
What does an inversely proportional relationship describe?
as one quantity increases, the other quantity decreases
A wrench applies a force of 40 N at a distance of 0.5 m from the pivot. What moment is produced?
20 N·m
Which one of these statements is correct?
A. Sound travels through empty space
B. Light needs air to travel
C. Waves transfer energy without transferring matter
D. Magnets attract every metal
C. Waves transfer energy without transferring matter
Why are door handles usually placed far from the hinges?
A bigger distance from the pivot requires less force, making the door easier to open
How can we create an electromagnet?
by coiling wires around a metal rod and passing a current through
What is meant by refraction?
the bending of light/sound as it passes through mediums due to a change in speed
Take Earth's gravitational acceleration as 9.8 m/s2. An object of 50 kg is lifted 4 m.
How much gravitational potential energy did the object gain?
1,960 J
Correlation or causation, & why?:
People who own horses live longer lives
correlation; hidden variable: they can afford medicine/healthy lifestyle