19. A planet's diameter is 2320 km, and its mass is 4.1 x 10^20 kg. The probe you landed on this planet weighed 1500 N on the earth. What did it weigh
on the surface of this planet?

20. threshold braking in the vehicle's braking system occurs when a. the brake pedal is pushed, heel on floorboard, with full foot pressure. b. the brakes are exerting full braking power, without traction loss. c. the driver begins pushing down the brake pedal, with moderate slowdown. d. the brakes just begin to take hold with a gradual slowdown.

Compare the patterns of the two waves shown in the image. which statement is true about these waves?

Match each type of lever with the correct diagram. 1. first-class 2. third-class 3. second-class