Iwill give the brainiest to whoever !
1. a force acting on an object does no work if
a. a machine is used to move the object
b. the force is not in the direction of the objects motion
c. the force is greater than the friction of motion
d. the object accelerates

2. a 120-meter long ski lift carries skiers from a station at the foot of a slope to a second station 40 m above. what is is the ima (ideal mechanical advantage) of the lift?
a.0.3
b.3
c. 40
d. 160

3. a mechanical device requires 420 j of work to do 230 j of work in lifting a crate. what is the efficiency of the device?
a. 0.5%
b. 190%
c. 55%
d. 183%