Question
A cube WXZY has sides of length 2.0 cm and mass 24.0 g. The cube rests on a metre rule of negligible mass. The geometrical centre of the cube is vertically above the 70.0 cm mark on the scale of the rule.
The cube has a non-uniform density so that its centre of gravity is not at its geometrical centre. The centre of gravity of the cube is in the plane of the diagram.
The rule rests on a pivot at the 50.0 cm mark. A mass of 23.4 g is placed vertically above the 30.0 cm mark. The rule is horizontal and in equilibrium.
What can be determined about the position of the centre of gravity of the cube?
A It must be somewhere along a horizontal line that is 0.5 cm from line WX.
B It must be somewhere along a horizontal line that is 0.5 cm from line YZ.
C It must be somewhere along a vertical line that is 0.5 cm from line WY.
D It must be somewhere along a vertical line that is 0.5 cm from line XZ.
Answer/Explanation
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Question
A cube WXZY has sides of length 2.0 cm and mass 24.0 g. The cube rests on a metre rule of negligible mass. The geometrical centre of the cube is vertically above the 70.0 cm mark on the scale of the rule.
The cube has a non-uniform density so that its centre of gravity is not at its geometrical centre. The centre of gravity of the cube is in the plane of the diagram.
The rule rests on a pivot at the 50.0 cm mark. A mass of 23.4 g is placed vertically above the 30.0 cm mark. The rule is horizontal and in equilibrium.
What can be determined about the position of the centre of gravity of the cube?
A It must be somewhere along a horizontal line that is 0.5 cm from line WX.
B It must be somewhere along a horizontal line that is 0.5 cm from line YZ.
C It must be somewhere along a vertical line that is 0.5 cm from line WY.
D It must be somewhere along a vertical line that is 0.5 cm from line XZ.
Answer/Explanation
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Question
A ball is rolling down a slope at a constant speed. The three forces acting on the ball are its
weight, the contact force normal to the slope and friction.
Answer/Explanation
Question
Three coplanar forces act on a block.
Which diagram shows the directions of the forces such that the block could be in equilibrium?
Answer/Explanation
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Question
A mass of 30 kg is suspended from the end of a wire. A horizontal force F acts on the mass so
that it is in equilibrium, with the wire at an angle of 30° to the vertical, as shown.
What is the magnitude of F?
A 17N B 150 N C 170 N D 510 N
Answer/Explanation
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