Mass, Weight & Density (CIE IGCSE Physics)

Topic Questions

1a4 marks

A student is determining the density of wood by two methods.

He is using the wooden rod shown in Fig. 1.1.

q1-image-1

Method 1

The dimensions of the wooden rod are shown full size in Fig. 1.2.

q1-image-2

(i)

Measure the length l and the diameter d of the wooden rod in Fig. 1.2.

l = ......................................................... cm

d = ......................................................... cm

[2]

(ii)

Suggest an accurate method for measuring the diameter of the wooden rod in this experiment.

List any additional apparatus that might be required and briefly describe how you would determine the diameter.

You may draw a diagram if it helps to explain your answer.

[2]

1b2 marks

The student uses a balance to measure the mass m of the wooden rod as shown in Fig. 1.3.

q1-b

Record the mass m of the rod.

 

 

m = ............................................................g

 

Calculate a value ρ1 for the density of the wooden rod. Use the values l = 4.5 cm and d = 2.0 cm, the value of the mass, and the equation rho subscript 1 equals fraction numerator 4 m over denominator pi d squared l end fraction. Include a suitable unit.

 

 

ρ1 = ........................................................

1c1 mark

Method 2

The student pours water into a measuring cylinder as shown in Fig. 1.4.
He then floats the wooden rod in the water as shown in Fig. 1.5.

q1-c

Record the reading V1 of the water level in the measuring cylinder as shown in Fig. 1.4.

 

 

V1 = ........................................................cm3

Record the new reading V2 of the water level in the measuring cylinder with the rod floating in the water as shown in Fig. 1.5.

 

 

V2 = ........................................................cm3

[1]

1d2 marks

The student removes the rod and lowers a piece of modelling clay into the water as shown in Fig. 1.6.

 

He then hooks the rod to the modelling clay and lowers them into the water as shown in Fig. 1.7.

q1-d

He records the new reading V3 of the water level in the measuring cylinder with the modelling clay.

He records the reading V4 of the water level in the measuring cylinder with the modelling clay and rod.

V3 = 164 cm3

V4 = 178 cm3

Calculate another value ρ2 for the density of the wooden rod. Use the values from (c) and (d) and the equation rho subscript 2 equals fraction numerator V subscript 2 minus V subscript 1 over denominator V subscript 4 minus V subscript 3 end fraction cross times k where k = 1.0 g/cm3.

ρ2 = ........................................................

1e1 mark

IBVhx0fL_q1-e

On Fig. 1.8, draw an arrow showing the correct line of sight for reading the volume of water in the measuring cylinder.

1f1 mark

Suggest a possible source of inaccuracy in Method 2, even if it was carried out carefully.

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2a2 marks
A student is determining the density of modelling clay.
    
He is using the block shown in Fig. 1.1 and Fig. 1.2.
screenshot-2022-11-11-at-11-56-23
(i)
Measure the dimensions of the block of modelling clay, as shown in Fig. 1.1 and Fig. 1.2.
   
   
length l = ........................................................ cm
width w = ........................................................ cm
height h = ........................................................ cm
[1]
 
(ii)
Calculate the volume V1 of the block, using your measurements from (a)(i) and the following equation:
V subscript 1 space equals space l space cross times space w space cross times space h
   
   
V subscript 1 = .................................................. cm3 [1]
 
2b2 marks

Suggest a possible source of inaccuracy in measuring the dimensions of the block and describe an improvement to the procedure that will produce more reliable measurements of the block.

2c1 mark

The student suspends the piece of modelling clay from a forcemeter, as shown in Fig. 1.3.

   
screenshot-2022-11-11-at-14-04-31

Record the weight W of the block of modelling clay shown in Fig. 1.3.

   
   
W = ..................................................... N 
2d2 marks

Calculate a value ρ1 for the density of the modelling clay, using your results from (a)(ii) and (c) and the following equation:

rho subscript 1 space equals space fraction numerator W space cross times space k over denominator V subscript 1 end fraction

Where k = 100 g/N.

   
   
ρ1 = ......................................................... 
2e2 marks

The student pours some water into a measuring cylinder, as shown in Fig. 1.4.

screenshot-2022-11-11-at-14-15-32
(i)
Record the volume V2 of the water in the measuring cylinder shown in Fig. 1.4.
   
   
V2 = .................................................. cm3 [1]
 
(ii)
Describe how a measuring cylinder is read to obtain an accurate value for the volume of water. You may draw a diagram to help you.
[1]
 
2f2 marks

The student lowers the modelling clay into the water, as shown in Fig. 1.5.screenshot-2022-11-11-at-14-21-30

(i)
Record the new reading V3 of the measuring cylinder Fig. 1.5, with the block of modelling clay in the water.
  
  

V3 = ....................................................... cm3

Calculate another value ρfor the density of modelling clay, using your value for V3, your readings from (c) and (e)(i) and the equation:
 
 
rho subscript 2 space equals space fraction numerator W space cross times space k over denominator open parentheses V subscript 3 space minus space V subscript 2 close parentheses end fraction 
where k = 100 g/N.
   
   
ρ2 = .............................................................. 
[1]
 
(ii)
Suggest which of ρ1 or ρ2 is likely to be the more accurate value for the density of the modelling clay.
   
Justify your answer by referring to the procedure.
[1]
 

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