Browse Forces & Newton's laws

182 questions at your level

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Force diagrams, resultant force & equilibrium

12 questions

LessonNot started
A particle is in equilibrium under three horizontal forces: 88 N to the right, 33 N to the left and a force PP to the left. Find PP.
●●●●●Level 22 marksStart
Three horizontal forces act on a particle: 1010 N to the right, 44 N to the left and 33 N to the left. Find the magnitude and direction of the resultant force.
●●●●●Level 22 marksStart
Find the weight of a particle of mass 55 kg. (g=9.8g = 9.8.)
●●●●●Level 22 marksStart

Newton's laws and F = ma

43 questions

LessonNot started
A particle of mass 55 kg accelerates at 4 m s−24\ \text{m s}^{-2}. Find the resultant force on it.
●●●●●Level 22 marksStart
A force of 66 N acts on a particle of mass 22 kg. Find the acceleration.
●●●●●Level 22 marksStart
Figure 1 shows a particle PP of mass 66 kg at rest on a rough horizontal plane.P (6 kg)Figure 1 — not accurately drawn
(a) Find the magnitude of the normal reaction of the plane on PP.

(1 mark)

The coefficient of friction between PP and the plane is 0.450.45

A horizontal force of magnitude XX newtons is applied to PP.

Given that PP is now in limiting equilibrium,
(b) find the value of XX.

(2 marks)
●●●●●Level 23 marksStart
A particle PP has mass 44 kg.

The particle is pulled along a rough horizontal plane by a horizontal force of magnitude 1818 N.

The only resistance to motion is a frictional force of magnitude FF newtons, as shown in Figure 1.P (4 kg)18 NF NFigure 1 — not accurately drawn
(a) Find the magnitude of the normal reaction of the plane on PP.

(1 mark)

The particle is accelerating along the plane at 2.5 m s−22.5\ \text{m s}^{-2}
(b) Find the value of FF.

(2 marks)

The coefficient of friction between PP and the plane is μ\mu
(c) Find the value of μ\mu, giving your answer to 2 significant figures.

(1 mark)
●●●●●Level 24 marksStart

Resolving forces

42 questions

LessonNot started
2 mαABCFigure 1

A uniform rod ABAB, of length 22 m and weight 3030 N, has its end AA freely hinged to a fixed point on a vertical wall. A particle of weight 1515 N is attached to the rod at BB. The rod is held in equilibrium in a horizontal position by a light inextensible string BCBC, where CC is a point on the wall vertically above AA. The string makes an angle α\alpha with the rod, where tan⁡α=34\tan\alpha = \frac34, as shown in Figure 1. The rod and the string lie in a vertical plane perpendicular to the wall. The tension in the string is 5050 N.

Find the magnitude of the force exerted on the rod by the hinge.

(4 marks)
●●●●●Level 24 marksStart
A force of 5050 N acts at 40∘40^\circ above the horizontal. Find its horizontal and vertical components, to 3 s.f.
●●●●●Level 22 marksStart
A force of 2020 N acts at 30∘30^\circ above the horizontal. Find its horizontal and vertical components, to 3 s.f.
●●●●●Level 22 marksStart

Forces on an inclined plane

29 questions

LessonNot started
A box of mass 55 kg rests on a smooth slope inclined at 20∘20^\circ. Find the normal reaction, to 3 s.f. (g=9.8g = 9.8.)
●●●●●Level 22 marksStart
A particle is released from rest on a smooth slope inclined at 30∘30^\circ to the horizontal. Find its acceleration. (g=9.8g = 9.8.)
●●●●●Level 22 marksStart

Friction

68 questions

LessonNot started
A uniform ladder, of weight 300300 N, rests in limiting equilibrium with its foot AA on rough horizontal ground and its top BB against a rough vertical wall. The ladder is inclined at 45∘45^\circ to the horizontal and lies in a vertical plane perpendicular to the wall. The coefficient of friction between the ladder and the wall is 0.250.25, and the normal reaction of the wall on the ladder has magnitude 120120 N.
(a) Find the magnitude of the normal reaction of the ground on the ladder.

(2 marks)
(b) Find the coefficient of friction between the ladder and the ground.

(2 marks)
●●●●●Level 24 marksStart
A uniform ladder, of weight 250250 N, rests with its foot on rough horizontal ground and its top against a smooth vertical wall. The ladder is in equilibrium but is not on the point of slipping. The normal reaction of the wall on the ladder has magnitude 6060 N. The coefficient of friction between the ladder and the ground is 0.40.4
(a) Find the magnitude of the frictional force acting on the ladder at its foot.

(2 marks)
(b) Find the magnitude of the resultant force exerted on the ladder by the ground.

(2 marks)
●●●●●Level 24 marksStart
Figure 1 shows a particle PP of mass 66 kg at rest on a rough horizontal plane.P (6 kg)Figure 1 — not accurately drawn
(a) Find the magnitude of the normal reaction of the plane on PP.

(1 mark)

The coefficient of friction between PP and the plane is 0.450.45

A horizontal force of magnitude XX newtons is applied to PP.

Given that PP is now in limiting equilibrium,
(b) find the value of XX.

(2 marks)
●●●●●Level 23 marksStart
A block of mass 44 kg rests on a rough horizontal surface with coefficient of friction 0.30.3. Find the least horizontal force needed to move it, to 3 s.f. (g=9.8g = 9.8.)
●●●●●Level 22 marksStart
A particle PP has mass 44 kg.

The particle is pulled along a rough horizontal plane by a horizontal force of magnitude 1818 N.

The only resistance to motion is a frictional force of magnitude FF newtons, as shown in Figure 1.P (4 kg)18 NF NFigure 1 — not accurately drawn
(a) Find the magnitude of the normal reaction of the plane on PP.

(1 mark)

The particle is accelerating along the plane at 2.5 m s−22.5\ \text{m s}^{-2}
(b) Find the value of FF.

(2 marks)

The coefficient of friction between PP and the plane is μ\mu
(c) Find the value of μ\mu, giving your answer to 2 significant figures.

(1 mark)
●●●●●Level 24 marksStart
A block of mass 22 kg rests on a rough horizontal surface with coefficient of friction 0.50.5. A horizontal force of 66 N is applied.

Determine whether the block moves, and state the magnitude of the frictional force acting. (3 marks)
●●●●●Level 23 marksStart