Sec1
Identify the physical quantity that is not scalar
a. speed
b. time
c. weight
d. energy
C. weight is a force. Forces have both magnitude and direction = vector quantity
Identify the physical quantity that is scalar
a. weight
b. distance
c. velocity
d. acceleration
distance. it has magnitude only.
A baker uses a balance to weigh out some ingredients to make bread. She weights out some white flour, then she weighs out some wholemeal flour. She notices that the reading on the balance is the same for both types of flour. The baker can conclude that the two flours have the same _____ .
weight
Which is an example of a force acting over a small area to produce a large pressure?
a. a skier wearing large skis on snow
b. a hammer being used to push a nail into a piece of wood
c. a tractor having very wide tires
d. a person lying down, rather than walking upright on a roof
B
The volume of a piece of brass is 16.3 cm3. A student measures its mass using an electronic balance. The mass of the brass is 138 g. The student notices that the electronic balance has a zero error, so it shows mass readings that are all slightly too small. Which sentence best describes the measured density?
a. Incorrect and slightly too large
b. Incorrect and slightly too small
c. Correct because the student sued three significant figures
d. Correct because the mass of the block is more than zero
B.
Density depends on mass, density is directly proportional to mass
A student is timing the rate of cooling of a beaker of water. on a repeat run of the investigation, the student forgets to zero the stopwatch. The reading on the stopwatch at the start time is 11 minutes & 19 seconds, and the end time is 23 minutes & 27 seconds. Calculate how long it took the beaker to cool in minutes and seconds
12 minutes and 8 Seconds
What is the speed of a bowling ball which travels down a 30 m lane in 2.5 seconds?
12 meters per second
The density of a block of wood is 2.7g/cm3 and mass of 583.3g. What is its volume?
density = mass /volume = 216 cm3
The driving force on a sports car has two forces that oppose the driving force. what are they?
DOUBLE JEOPARDY
Any two:
braking force, air resistance/drag, tire&road friction
Where does sound travel faster; water or air?
water
A student is trying to see how quickly they can run 5.0 km on a standard 400 m running track. They reason that, if they know how fast they can run one lap, they can assume they will run at the same speed for 5.0km and can calculate their predicted time. They, correctly reason that they will not be able to maintain their initial pace throughout the whole 5.0 km, so they decide to time lap 5. Start of lap is 9 minutes and 13 seconds, end of lap at 11minutes and 10 seconds.
Calculate how long it should take the student to run 5.0km.
24 minutes and 22.5 seconds
During a Go Karting race, a car does 8 laps of a 300 m course. it takes 4.0 minutes to complete the race. What was the average speed of the Go Kart?
(300*)/(4.0*60) = 10m/s
A motorbike travels at a constant speed along a flat road. Three horizontal forces act on the motorbike. Two of them are:
To the back = 800N
Forward = 2000 N
Direction of motion = forwards
What is the size and direction of the third force?
1200 N backwards
tip: constant speed, thus the resultant force is 0N
force forward is 1200 N (2000N-800N)
Thus, a force of 1200 N backwards is required to give a resultant force of 0N
A student investigates the motion of different falling masses by measuring the time taken for empty cupcake cases to fall from a window. The student drops one case from the window. He repeats the experiment with two cases stuck together then with three cases and then with four. Name two measuring instruments that he would need for his investigation.
DOUBLE JEOPARDY
Any two from:
1. balance to measure the mass of the cases
2. stopwatch to measure the time for the cases to fall
3. A metre ruler to measure the distance fallen.
What is the law of conservation of energy?
energy is nether created or destroyed "energy of the Universe is constant"