# physics

posted by .

A 9.90-g bullet has a speed of 1.33 km/s.
(a) What is its kinetic energy in joules?
(b) What is the bullet's kinetic energy if its speed is halved?
(c) What is the bullet's kinetic energy if its speed is doubled?

• physics -

K = 1/2 mv2

plug in your numbers for m and v to get K.

Since K varies as v2, if the speed changes by a factor of 2, the energy changes by a factor of 22=4

## Similar Questions

1. ### physics

A gun is fired vertically into a 1.55 kg block of wood at rest directly above it. If the bullet has a mass of 21.0 g and a speed of 190 m/s, how high will the block rise into the air after the bullet becomes embedded in it?
2. ### Physics

A 2.50g bullet, traveling at a speed of 425m/s, strikes the wooden block of a ballistic pendulum. The block has a mass of 270g (a) find the speed of the bullet/block combination immediately after the collision (b) how high does the …
3. ### Physics

A pitcher claims he can throw a 0.157 kg baseball with as much momentum as a 1.5 g bullet moving with a speed of 1.50 multiplied by 103 m/s. (a) What must the baseball's speed be if the pitcher's claim is valid?
4. ### physics

A 9.50 {\rm g} bullet has a speed of 1.40 {\rm km/s}. What is its kinetic energy in joules?
5. ### physics

A 9.90-g bullet has a speed of 1.33 km/s. (a) What is its kinetic energy in joules?
6. ### Algebra II

The kinetic energy of a moving body is directly proportional to its mass and the square of its speed. If the mass of a bullet is halved, by what factor must its speed be increased to have the same kinetic energy as before?
7. ### physics

A bullet with mass m = 5.21 g is moving horizontally with a speed v=367 m/s when it strikes a block of hardened steel with mass M = 14.8 kg(initially at rest). The bullet bounces o the block in a perfectly elastic collision. (a) What …
8. ### AP physics

A 1.60-g bullet, moving at 542 m/s, strikes a 0.249-kg piece of wood at rest on a frictionless table. The bullet sticks in the wood, and the combined mass moves slowly down the table. (a) Find the speed of the combination after the …
9. ### Physics !!!!! HELP PLEASE

A hand gun fires a 12.0 g bullet at a speed of 400 m/s. What is its kinetic energy?
10. ### mambane

A 10.0g bullet is fired with a speed of 500m/s into a pendulum block of mass 5.00kg, suspended from a cord 0.600m long. Calculate: (a)the vertical height through which the pendulum rises. (b) the initial kinetic energy of the bullet. …

More Similar Questions