Revision for Assessment 2

Define Newton First Law

• Whenever two bodies interact, the two forces that they exert on each other are always equal in magnitude and opposite in direction

• Acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass

• An object will remain at rest or moving at a constant velocity, until it experiences a resultant force

What is meant by linear equilibrium? Select all possible answer/s.

• The net force is equal to zero

• Fnet=0

• a=0

• F 1 on 2 = - F 2 on 1

A block of mass 𝑚1 = 3.70 𝑘𝑔 on a rough plane inclined at angle 𝜃 = 30.0° with the horizontal. Which of the following is the correct free body diagram?

• 
• 
• 

What is the minimum horizontal force to stop a 40 kg box from sliding down an inclined plane of coefficient of friction 0.2. Given that the plane is 50° to the horizontal?

• 494.82 N

• 315.06 N

• 308.00 N

• 498.71 N

Find the magnitude of the tension in the string if the mass of the object is 5 kg and the force apply at the end of the string is 49.05 N and the system is static.

• 7.84 N

• 49.05 N

• 10 N

• 24.53 N

A 75.0 kg painter climbs a ladder that is 2.75 m long leaning against a vertical wall. The ladder makes an angle of 30° with the wall. How much work does gravity do on the painter?

• 1709.24 J

• 876.12 J

• 1752.24 J

• 1876.54 J

A 2 kg sphere slides down a smooth and curvy surface as shown in Figure. The sphere is initially at rest. Use the conservation of energy to calculate the velocity of the sphere at point D.

• 15.97 m/s

• 14.02 m/s

• 19.81 m/s

The diagram below shows a body mass 5.0 kg placed 1.0 m high on an inclined plane with base length 3.0 m. If the body slides down the inclined plane with coefficient of kinetic friction equal to 0.2, calculate the work done against friction.

• -19.59 J

• -29.41 J

• 2.90 J

Calculate how much work is required for 80.0 kg boy to accelerate from rest to 3.5 ms^-1.

• 490 J

• 140 J

• -490 J

• -140 J

How much power is delivered by a 80.0 kg boy to accelerate from rest to 3.5 ms^-1 in 3 s.

• 163.33 J

• 46.67 W

• 125.46 W

• 163.33 W