A Rock Of Mass M Is Thrown Horizontally

Question: Write the formula for the work done by a force

Answer: W=Fdcostheta

Question: Write the formula for kinetic energy

Answer: KE=1/2mv²

Question: Write the formula for gravitational potential energy

Answer: PEg=mgh

Question: Write the formula for elastic potential energy

Answer: PEs=1/2kx²

Question: Write the unit for work

Answer: Joules, J

Question: A 2 kg book is held 2 m above the floor for 50 s. The work done is

Answer: 0

Question: When the velocity of a moving object is double

Answer: its kinetic energy increases by a factor of 4

Question: a rock of mass m is thrown horizontally off a building from a height h, as shown at right. The speed of the rock as it leaves the thrower’s hand at the edge of the building is Vo. What is the kinetic energy of the rock just before it hits the ground?

Answer: (1/2)mVo²+mgh

Question: Unlike the previous problem, a rock of mass m is dropped from the top of a building of height h. What is the kinetic energy of the rock just before it hits the ground?

Answer: mgh

Question: An arrow in a bow has 70 J of potential energy. Assuming no loss of energy due to heat, how much kinetic energy will the arrow have immediately after is has been launched?

Answer: 70 J