Question
(a) Fig. 2.1 shows a brick.
500 bricks like the one shown in Fig. 2.1 are stacked on a wooden platform, known as
a pallet. The pallet of bricks is to be loaded on to a lorry by means of a fork-lift truck,
as shown in Fig. 2.2.
Each brick has a volume of 0.0012 m3 and is made of a material of density 2300 kg / 
.
1.Calculate the mass of one brick.
mass = ……………………………………. kg [3]
2.The fork-lift truck can safely lift a load of mass 2 tonnes (2000 kg). The wooden
pallet has a mass of 100 kg.
1.Calculate the total mass of the pallet and 500 bricks.
total mass =…………………………………………. kg
(a). Is it safe for the fork-lift truck to lift the total mass of the pallet and 500 bricks? yes
[3]
(b) The brick shown in Fig. 2.3 has the same dimensions as the brick in Fig. 2.1 and is
made of the same material. However, this brick has a hollow in one face.
Complete the following sentences.
(i) The density of the brick in Fig. 2.3 is the density
of the brick in Fig. 2.1, because ………………………………………………………….
………………………………………………………….……………………………………………
(ii) The mass of the brick in Fig. 2.3 is the mass of the brick in Fig. 2.1. [2]
[Total: 8]
Answer/Explanation
Ans: (a) (i) D = M / V in any form OR D × V 2300 × 0.0012 2.76 OR 2.8 (kg)
(ii) (mass of bricks =) 500 × 2.76 OR 500 × candidate’s (a)(i) (total mass = ) 1480 OR e.c.f. candidate’s (a)(i) yes / no ticked (expect yes), must be compatible with candidate’s total mass
(b) (i) the same because made of same material
(ii) less than OR equivalent answer
Question
Fig. 3.1 and Fig. 3.2 show how a puddle of water changes on a warm windy day.
(a) Describe the process by which the volume of water in the puddle decreases.[2]
(b) State and explain one change in the weather that would cause the volume of water in the puddle to decrease more slowly. [2]
statement
explanation
(c) Explain, in terms of molecules, how sweating helps to cool your body on a hot day. [3] [Total: 7]
Answer/Explanation
Ans:
(a) Any two from:
- (Amount of water in the pool decreases) as water evaporates / becomes water vapour / gas
- The (more) energetic molecules escape OR fast(er) molecules escape OR molecules with more (kinetic) energy escape
- From the surface of the water
(b)
(c) Any three from:
- (thermal) energy in the skin / body transferred to (molecules of) sweat
- These molecules (have enough KE to) escape from the skin / become water vapour
- Leaving behind molecules with lower energy
- Which leaves the skin / body at a lower temperature