Cual es la eficiencia de un motor que produce 0.5 hp con una entrada de 340 w​

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

Ahanging spring stretches by 35.0 cm when an object of mass 450 g is hung on it at rest. in this situation, we define its position as x = 0. the object is pulled down an additional 18.0 cm and released from rest to oscillate without friction. what is its position x at a moment 84.4 s later? express your answer in cm.

What does the law of conservation of mass state?