Analysing force problem Watch
A ball of mass 9.3kg rests on a ramp that makes an angle of 18◦ with
the horizontal. It is held in place by a rope that makes an angle of 42◦
with the horizontal, as shown in the diagram. Assume that the only
forces acting on the ball are its weight, the tension in the rope and the
normal reaction from the ramp. Take the magnitude of the
acceleration due to gravity to be g = 10ms−2.
1. Draw a force diagram for the forces acting on the ball, defining
the symbols that you use to denote the forces, and indicating the
sizes of the angles between the forces.
2. Draw a corresponding triangle of forces, indicating the sizes of the
3. Use the triangle of forces to find the magnitudes of the tension in
the rope and the normal reaction from the ramp, to the nearest
...and the angle between 42 degrees and 18 derees is a right angle??
i dont understand 'And the normal reaction at right angles to the ball.'
The normal reaction makes an angle of 18 degrees with the upward vertical.
The tension makes an angle of 48 degrees with the upward vertical.
Draw a line downwards to represent the weight. Then go off to the right, making an angle of 18 degrees with the upwards vertical. Finally, go to the left, making an angle of 48 degrees with the upward vertical. When you hit your weight line, you'll have your triangle of forces.