worksheet 3a.1 2011
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worksheetTRANSCRIPT
Worksheet 3A.1 Page 1 Prepared by: Mr Melvin Ng
Changkat Changi Secondary School Physics Department
4E/5NA
Name: _________________________( ) Class: ____________ Date: ______________ TOPIC : Dynamics ( Vectors & Scalars)
WORKSHEET 3A.1 1. There are two kinds of quantities in Physics, scalars and vectors. [4]
(a) What is the difference between a vector quantity and a scalar quantity? ______________________________________________________________________ ______________________________________________________________________ (b) Give one example of a vector quantity and one example of a scalar quantity. Vector quantity _______________________________. Scalar quantity _______________________________.
2. Forces are applied to a box in a few cases shown below. For each diagram, draw the
resultant force on the box next to it. You need not draw to scale. [4] (a)
(b)
(c)
(d)
7 N 3 N
3 N 3 N
6 N
4 N
5 N
5 N
18
Worksheet 3A.1 Page 2 Prepared by: Mr Melvin Ng
3. A mass is acted on by two forces, each of 12 N. The forces are at an angle of 40o to each other as shown in the figure below. [2]
Using a scale of 1 cm to 2 N, draw a vector diagram to determine the resultant force acting on the mass.
4. A lorry is being pulled by two jeeps. Each jeep exerts a force of 4000 N at an angle of 15o to the horizontal in the direction shown. [2]
Using a scale of 1 cm to 800 N , draw a scaled diagram to find the resultant force pulling the lorry forward.
15o
15o
4000 N
4000 N
12N
20o
12N
20o
Worksheet 3A.1 Page 3 Prepared by: Mr Melvin Ng
5. A mass of weight W is supported by two strings as shown. The tension in each string is 10 N.
(i) Using a scale of 1 cm to 2 N, determine the upward force required to balance the weight
W. [2] (ii) Hence, determine the mass of W. [1]
60o 60o
W
10 N10 N 60o
Worksheet 3A.1 Page 4 Prepared by: Mr Melvin Ng
6. Fig 3.1 shows a lantern that is held by two wires. The tension in each wire is 16N and the angle between the wires is 120o
(i) Draw a vector diagram to scale in order to determine the resultant force. State the scale used. Scale: 1 cm represents ……………………….. [2] (ii) Hence, state the weight of the lantern.
Weight = …………………………………. N [1]
Fig. 3.1
16 N 16 N
120o