O level Physics Dynamics (10 qns)

A pendulum bob of mass 2.9 kg is pulled horizontally to the left by a 30 N force as shown. Which will be the approximate final tension in the string when the bob is in equilibrium?

• 30 N

• 36 N

• 40 N

• 45 N

Tags

NGSS.HS-PS2-1

A constant force of 40 N acts on an object of mass 2.0 kg. The object moves along a rough horizontal surface with an acceleration of 5.0 m/s². What is the average frictional force acting on the object?

• 8.0 N

• 10 N

• 30 N

• 50 N

Tags

NGSS.HS-PS2-1

A wooden block that is pushed along a horizontal flat surface moves at a constant speed. Which statement is correct?

• The frictional force is greater than the pushing force

• The frictional force is equal and opposite to the pushing force

• The frictional force is less than the pushing force

• The frictional force is increases as the block moves at constant speed

Tags

NGSS.HS-PS2-1

Which pair of forces is a pair of action-reaction forces?

• Force pulling a rope and tension in the rope

• Thrust acting on a car and air resistance acting on the car

• Upward force acting on a plane and weight acting on the plane

• Gravitational force on a book and reaction force acting on the book

Tags

NGSS.MS-PS2-1

What needs to change when a body is accelerating

• The mass of the body

• The resultant force of the body

• The speed of the body

• The velocity of the body

Tags

NGSS.HS-PS2-1

A cyclist is riding at a steady speed on a level road. According to Newton's Third Law of motion, what is the equal and opposite force to the backward push of the back wheel on the road?

• The tension in the cycle chain

• The total air resistance and frictional force

• The force exerted by the cyclist on the pedals

• The forward push of the road on the back wheel

A nail is fixed firmly to a wall. It is pulled by a string at 40° to the vertical. The nail does not move. Which diagram represents the three forces. weight (W), tension (T) and reaction force (R) in size and direction?

• 
• 
• 
• 

Tags

NGSS.HS-PS2-1

A helicopter of mass 3.0 x 10³ kg rises vertically with a constant speed of 25 m/s. The gravitational field strength g is 10 N/kg. What is the resultant force acting on the helicopter?

• 0 N

• 3.0 x 10⁴ N downwards

• 4.5 x 10⁴ N upwards

• 7.5 x 10⁴ N upwards

Tags

NGSS.HS-PS2-1

The diagram shows the velocity-time graph of a car. The total resistive force acting on the car os 1000 N. The mass of the car 1000 kg. What is the resiltant force acting on the car at t = 4.0s?

• 0 N

• 4000 N

• 5000 N

• 6000 N

Tags

NGSS.HS-PS2-1

Two forces F1 and F2 act on a particle P. A third force F3 is required to keep the system in equilibrium. The graph is not drawn to scale. What is the magnitude of F3?

• 4.0 N

• 4.5 N

• 5.5 N

• 5.8 N

Tags

NGSS.HS-PS2-1