An object of mass 800g hangs on a spring. Calculate the force exerted by the object if g =10ms^2

Acar going 10 m/s starts accelerating at a rate of 3 m/s2 for 4 seconds calculate the final velocity of the car

Mechanical energy is when there are no forces causing an object to lose energy. a. increased b. conserved c. decreased d. doubled i need this answer ! .

The topics covered by the study of thermodynamics include a. energy changes during heating. b. energy changes during chemical reactions. c. color changes during chemical reactions. d. both (a) and (b)