EQUILIBRIUM OF FORCES

A particle is kept in equilibrium by the action of three coplanar forces, B=6N, C=9N and D=4.5N. If the angle between B and C is 30°, find the angle between B and D.

• 90°
• 60°
• 45°
• 30°

A body, M, is maintained in equilibrium by three forces as shown in the diagram below. Calculate, correct to one decimal place, the value of R.

• 115.0N
• 79.4N
• 75.8N
• 34.4N

A body of mass 40Kg is suspended with an inelastic string as shown in the diagram. If the system is in equilibrium, find, in terms of g, the tension T in Newton in the string.

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A uniform beam, PQ of length 100cm weighs 35N. It is placed on a support at a point 40cm from P. Weights of 54N and W are attached to P and Q respectively to keep the beam in equilibrium. Find, correct to the nearest whole number, the value of W.

• 69N

• 60N

• 35N

• 30N

A uniform bar PQ, of length 16m, is pivoted at its centre of gravity and a weight of 60N is suspended 1.5m from P. Find how far from Q, a weight of 150N is suspended if the bar rests horizontally.

• 2.6m
• 3.8m
• 5.4m
• 6.5m

A uniform horizontal beam AB of weight 18N and length 90cm is supported on two pivots. One pivot P is 20cm from one end and the other pivot Q is 12cm from the other end. Calculate, to four significant numbers, the reaction at the pivot P.

• 10.24N

• 7.59N

• 11.75N

• 18N

An object weighing 30N is kept in equilibrium by two strings P and Q inclined at 30° and 60° respectively to the horizontal. Find the tension in the string P in Newtons.

• 15N

• 16N

• 17N

• 18N

A uniform beam PQ of length 100cm and of weight 25N lies on a support 30cm from the end P. Weights 70N and W are attached to the ends P and Q respectively, to keep the beam in equilibrium. Find the value of W, to the nearest whole number.

• 20N

• 21N

• 22N

• 23N

• 150N

• 160N

• 170N

• 175N

A uniform rod PQ, 20cm long and weighing 80N has weights 20N and 50N suspended at P and Q respectively. Find the distance from P where the rod must be supported so that it will rest horizontally.

• 12cm

• 13cm

• 15cm

• 22cm