A large rock is motionless on a flat sidewalk. Which statement best explains why the rock remains motionless? A: The sidewalk exerts an unbalanced force on the rock.
B:The only force acting on the rock is directed toward the sidewalk.
C:The forces acting on the rock are all balanced.
D:There are no forces acting on the rock

An object is located 30.0 cm from a concave mirror. the focal length is 15.0 c,. what is the image distance? a. 30.0 cm b. -10 cm c. 10.0 cm d. -30.0 cm

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

Crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied