1. On a sunny spring day, Mr. Hane's family went to a zoo in his town. His daughter looked at an elephant, and she found that the mass of the elephant is 2019 kg. What is the weight of the elephant in Newtons? Use the acceleration due to gravity (g) as 9.8 meters per second squared.
2. Bobby and Alice are pushing a stalled car in the same direction. The mass of the car is 2,000 kg. Bobby applies 400 N to the car while Alice applies 300 N. A force created by friction is 500 N in the opposite direction. What is the acceleration of the car?
3. Katie pushes her boyfriend, Gabe, on an ice rink with a force of 30 N. The masses of Katie and Gabe are 60 kg and 90 kg, respectively. Calculate the acceleration of Katie and that of Gabe.
4. The gravity on the surface of Mars is approximately 38% of the gravity on Earth. The gravitational acceleration on the surface of the Earth is 9.8 meters per second squared. That of Mars is 3.7 meters per second squared. What is the weight of a 100-kg object on Mars and on Earth?
5. Two forces of 11 N and 33 N are applied to a 22 kg box. Find (1) the box's acceleration when both forces point due east and (2) the box's acceleration when 11 N points due east and 33 N points due west.
6. A newly invented ride called Crazy Box in an amusement park has a strong magnet. The magnet accelerates the boxcar and its riders from zero to 35 m/s in 5 seconds. Suppose the mass of the boxcar and riders is 6,000 kg. What is the acceleration of the boxcar and its riders? What is the average net force exerted on the boxcar and riders by the magnets?
7. Suppose you are in an accelerated elevator. Your weight on earth is 700 N. If the acceleration is the same as the earth's gravitational acceleration, what is your apparent weight?
8. If a 2 kg object travels at a constant speed of 3 m/s, what is the kinetic energy of the object? (10 points) Hint: See Section 6.2 in the textbook.
9. If the height of an object is 5 m and its mass is 3 kg, what is the gravitational potential energy of this object? Here, the gravitational acceleration g is given by 10 m/s².