1. How many protons does14/6C atom contain?

2.A hydrogen balloon that provides a 30 N upward force is connected to a 2 kg gift package with weight downward. What is the acceleration (in m/s²) of the package going up?

3.A car speeds up uniformly from 10 m/s to 20 m/s while traveling a distance of 75 m. What is its acceleration (in m/s²) during this time?

4.A large star of 10¹⁸ kg and a small star are 10⁵ meters apart and attract with 6.7 N. What is the mass of the small star (in kg)?

5.A car travels at 10 m/s for 20 seconds and then at 20 m/s for 30 seconds. What is the average speed (in meter/second) for the trip?

6.A car initially traveling at 50 m/s slows down at -10 m/s² for 4 seconds. How far (in meter) does it travel during the 4 seconds?

7.A car at rest accelerates at 6 m/s². How far (in meter) does it travel in the first 3 seconds?

8.A car engine with engine efficiency 40% burns gasoline and does 500 Joule work to drive the car. How much heat (in Joule) is produced from gasoline burning (hot source)?

9.The specific heat of water is 1.0 cal/gram ^oC. 100 gram hot water at 100 ^oC is mixed with 300 gram cold water at 20 ^oC. What is the final equilibrium temperature (in ^oC) of the mixed water?

10.A ball of 1 kg is shot vertically upward with 20 m/s from the ground. What is the kinetic energy (in Joule) on its way upward at a height of 10 meters above the ground?

11.A spring gun with spring constant 4000 N/m is compressed 10 cm from its natural length and then shoots a bullet out of the gun to 20 m/s. What is the mass of the bullet (in kg)?

12.A spring gun with spring constant 9800 N/m is compressed 10 cm from its natural length and then shoots a ball of 1 kg vertically upward. What is the maximum height the ball can reach (in meter)?