Screw driver and scissor are called …………
a) Simple machines
b) Cutters
c) Lifter
d) Complex machines
Speed of a car can be changed by …………
a) Hammering
b) Stretching
c) Twisting
d) Applying force
An example of simple machine is …………
a) Stapler
b) Electric generator
c) Steam engine
d) Electric motor
Force can………………
a) Speed up
b) Slowdown
c) Stop an object
d) all of these
Friction between moving parts of machine causes………….
a) Heat
b) Light
c) Energy
d) Oil
Force of friction always opposes pushing force
and motion. Friction is due to: PST ---P-1----18L
a) Mass of body
b) Relative acceleration of body and surface below
c) Relative velocity of body and surface below
d) contact between a body and surface below
