Sec 2 Revision 1

Force and pressure

100

formula to calculate force

F = mg

200

formula to calculate pressure and its unit

P = F/ A, unit of pressure is Pa

300

list two non-contact force and one contact force

gravitational force, magnetic force and friction

400

If a mango's mass is 2 kg. Calculate its weight on the Mars if the gravitational field strength on Mars is 3.8N/kg.

7.6 N

500

If a pen and a nail has equal mass, which one will exert more pressure on the surface of a table? explain.

A nail. As the nail has smaller contact area with the surface of a table, thus the pressure exerted will be greater.

Work done and energy

100

What is energy?

It is the ability to do work.

200

Calculate work done if a man use 1000N of force to push a wall.

0 J.

300

Why a man does no work as he pushes against a wall?

Although the man applied force to push the wall, but it never move.

400

State energy conversion when a house use solar energy to charge a powerbank.

Light energy --> electrical energy --> chemical potential energy

500

Calculate work done by a man as he walk up the stairs from level one to level two. The distance between each level is 4m and his body mass is 70kg.

2800J

Heat and ecosystem

100

Upon heating, which of the following expands the slowest?

A. carbon dioxide

B. water

C. plastic bag

C

200

Which of the following medium prevent conduction and convection?

A. air

B. rubber

C. vacuum

C

300

Grass --> grasshopper --> fox --> tiger

Which organism is in the third trophic level?

fox

400

What is the relationship between a sea anemone and a clown fish?

mutualism

500

Polar bear has white fur. Explain how its fur reduce heat loss.

White is poor radiator of heat. Less heat is radiated from polar bear's body so as to keep it warm.

Electricity

100

The SI unit of current

Ampere

200

In a series circuit, the batteries provide 6V of voltage and the resistance of two light bulbs is 3 ohm each. Calculate total amount of current flow through the circuit.

2A

300

In a parallel circuit, the batteries provide 6V of voltage and the resistance of two light bulbs is 3 ohm each. Calculate total amount of current flow through the circuit.

4A

400

How to place ammeter and voltmeter in a circuit? Explain.

Ammeter in series while voltmeter in parallel. Ammeter has very low resistance while voltmeter has high resistance

500

The power rating of a table lamp is 30W. If Ben uses his table lamp everyday for 8 hours and the cost for electricity is 28 cents per unit. Calculate the amount he has to pay for using the lamp in September.

201.6 cents / $2.02