Asystem with one fixed and one moveable pulley operates with 90% efficiency. the moveable pulley has a weight of 5 n. using this pulley system, what is the minimum input force needed to lift a piano weighing 1,595 n?

Answer

800 N

Explanation

Efficiency = (mechanical advantage)/(velocity ratio) × 100%

Mechanical advantage (M.A) = Load/Effort

                                      = (1,595+5)/Effort

                                      = 1,600/Effort

Velocity ratio = 2

90/100 = M.A/2

M.A = 0.9 × 2

       = 1.8

M.A = 1,600/Effort

2 = 1,600/Effort

Effort = 1600/2

        = 800 N

hi i’m sorry to call us today so we will get back with y’all and we will have to do it haha omg was the day

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.