Question: The end of the cutting cord on a gas-powered weed cutter is 0.15 m in length. If the motor rotates at the rate of 20 rev/s, what is the tangential speed of the end of the cord?
Answer: 19 m/s
Question: A roller coaster, loaded with passengers, has a mass of 2 500 kg; the radius of curvature of the track at the top point is 20 m. If the vehicle has a speed of 25 m/s at this point, what force is exerted on the vehicle by the track?
Answer: 5.4 x 10⁴ N
Question: An object of mass 0.50 kg is transported to the surface of Planet X where the object’s weight is measured to be 20 N. The radius of the planet is 4.0 x 10⁶ m. What free fall acceleration will the 0.50-kg object experience when transported to a distance of 2.0 x 10⁶ m from the surface of this planet?
Answer: 18 m/s²
Question: An Earth satellite is orbiting at a distance from the Earth’s surface equal to one Earth radius (4 000 miles). At this location, the acceleration due to gravity is what factor times the value of g at the Earth’s surface?
Answer: 1/4
Question: An object when orbiting the Earth at a height of three Earth radii from the center of the Earth has a weight of 1.00 N. What is the object’s mass?
Answer: 0.92 kg
Question: A careful photographic survey of Jupiter’s moon Io by the spacecraft Voyager 1 showed active volcanoes spewing liquid sulfur to heights of 70 km above the surface of this moon. If the value of g on Io is 2.0 m/s², estimate the speed with which the liquid sulfur left the volcano.
Answer: 530 m/s
Question: The escape speed from the surface of the Earth is 11.2 km/s. Estimate the escape speed for a spacecraft from the surface of the Moon. The Moon has a mass 1/81 that of Earth and a radius 0.25 that of Earth.
Answer: 2.5 km/s
Question: An object of mass 0.50 kg is transported to the surface of Planet X where the object’s weight is measured to be 20 N. The radius of the planet is 4.0 x 10⁶ m. What is the mass of Planet X? (G = 6.67 x 10⁻¹¹ N·m²/kg²)
Answer: 9.6 x 10²⁴ kg
Question: An object of mass 0.50 kg is transported to the surface of Planet X where the object’s weight is measured to be 20 N. The radius of the planet is 4.0 x 10⁶ m. What free fall acceleration will the 0.50-kg object experience when at the surface of Planet X?
Answer: 40 m/s²
Question: Geosynchronous satellites orbit the Earth at a distance of 42 000 km from the Earth’s center. Their angular speed at this height is the same as the rotation rate of the Earth, so they appear stationary at certain locations in the sky. What is the force acting on a 1 500-kg satellite at this height?
Answer: 339 N
Question: A rod of length L is pivoted about its left end and has a force F applied perpendicular to the other end. The force F is now removed and another force F’ is applied at the midpoint of the rod. If F’ is at an angle of 30° with respect to the rod, what is its magnitude if the resulting torque is the same as when F was applied? (4F)
Answer Options:
4F
2F
F
8F
Answer: 4F