Physics Around Us
Space & Universe
Lab & Measurement
Physics Intuition
Weird Physics
100
A car travels 100 km in 2 hours. What is its average speed?
50 km/h
100
Which planet is closest to the Sun?
Mercury.
100
Which instrument would you use to measure the length of a table?
Ruler / metre rule / tape measure.
100
A bus suddenly brakes. Your body seems to move...
A) forwards
B) backwards
C) upwards
D) nowhere
A — forwards, because of inertia.
100
What is the fastest known speed in the universe?
The speed of light in vacuum, approximately 3.0×108 m/s.
200
What type of electrical current comes from a normal wall socket: AC or DC?
AC
200
Approximately how long does light take to travel from the Sun to Earth?
A) 8 seconds
B) 8 minutes
C) 80 minutes
D) 8 hours
B — about 8 minutes 20 seconds.
200
What is the SI unit of force?
Newton (N).
200
A truck collides with a small car.
Which vehicle experiences the greater force during the collision?
Neither — the forces are equal in magnitude.
200
Which is closest to absolute zero?
A) −100 °C
B) −273 °C
C) −500 °C
D) 0 °C
B — approximately −273.15 °C.
300
Ignoring air resistance, which falls faster: a 1 kg ball or a 10 kg ball?
They fall at the same rate.
300
An astronaut standing on the Moon has less...
A) mass
B) weight
C) both
D) neither
B — weight.
300
You measure the same length three times and get:
15.2 cm, 15.3 cm, 15.2 cm
What should you do with these measurements to get your best estimate?
A) Use the largest value
B) Use the smallest value
C) Calculate the mean
D) Add them together
C — Calculate the mean
300
You are standing on bathroom scales inside an elevator. The elevator begins accelerating upwards.
Does the scale reading:
A) increase
B) decrease
C) stay the same
A — increase.
300
Which reaches you first during a thunderstorm: the light from the lightning or the sound of thunder?
Light
400
Why can't you hear an explosion in space?
Sound requires a medium through which to travel.
400
A light-year measures what?
Distance, not time.
400
Why might a physicist repeat the same measurement several times?
To reduce the effect of random uncertainty / obtain a more reliable mean.
400
There is gravity on the International Space Station. So why do astronauts appear weightless?
They and the ISS are continuously falling/orbiting Earth together.
400
Superman pushes a huge asteroid in empty space.
Once he stops pushing it, what happens?
A) It immediately stops
B) It gradually slows down
C) It continues moving
C — it continues moving at constant velocity, assuming no resultant force acts on it.
500
You double the speed of a moving car. By what factor does its kinetic energy increase?
Four times.
500
A galaxy is 2 million light-years away. Approximately how old is the light we see from it?
2 million years.
500
You have only a stopwatch.
How could you determine the period of a swinging pendulum as accurately as possible?
Time many oscillations and divide the total time by the number of oscillations.
500
Could you walk normally if there were no friction whatsoever between your shoes and the floor?
No — you need friction to push against the ground.
500
Your nervous system communicates partly using electrical signals.
Approximately how fast can the fastest nerve signals travel?
A) 1 m/s
B) 10 m/s
C) 100 m/s
D) 3×108 m/s
C — roughly 100–120 m/s.