Which undergoes a physical change if it is heated at 50 degrees celcius?

An object weigh 40n in air ,weigh 20n when submerged in water,and 30n when submerged in a liquid of unknown liquid density.what is the density of unknown of liquid?

What does the negative sign in f = –kx mean?

4. a car with a mass of 2,200 kg can accelerate from 0 to 30 m/s in 6 seconds. a. assuming all of the force generated by the engine goes into acceleration of the car, how much force is the engine producing? show your work. (6 points)