Laws of Motion

Q1.The normal force on a block kept on a horizontal surface depends on which of the following:

• AThe speed of the block
• BThe weight of the block (and any vertical forces)
• CThe horizontal force applied
• DThe coefficient of friction

Q2.Kinetic friction is generally taken as:

• Agreater than maximum static friction
• Bequal to maximum static friction
• Cless than maximum static friction
• Dindependent of speed always

Q3.Four forces of 1 N, 2 N, 3 N, and 4 N act on an object. For the object to be in equilibrium, a 5th force must have magnitude:

• A10 N
• Bbetween 0 and 10 N
• Cexactly equal to the resultant of the four forces
• Dcannot be determined

Q4.A spring scale reads 50 N when an object is suspended at rest. If the system is in free fall, the reading is:

• A50 N
• B25 N
• C100 N
• D0 N

Q5.A 70 kg man stands on a weighing machine in a lift. The machine reads 56 kg. The lift's acceleration is (g = 10 m/s^2):

• A2 m/s^2 downward
• B2 m/s^2 upward
• C9.8 m/s^2 downward
• D4 m/s^2 downward