Question 25 (1 point) 20 seconds after starting from rest, a freely falling object on Earth will have a speed of about m/s. Your Answer: Answer Question 26 (1 point) A 7 kg mass at Earth's surface weighs about_ N. Your Answer: AnswerQuestion 7 (1 point) A tow truck exerts a force of 4,000 N on a car, accelerating it at 3 m/s2. What is the mass of the car, in kg? Your Answer: Answer Question 8 (1 point) A car has a mass of 900 kg and accelerates at 3 m/s2. What is the magnitude of the force, in N, exerted on the car? Your Answer: AnswerQuestion 35 (1 point) An object is pulled northward with a force of 9 N and southward with a force of 14 N. The magnitude of the net force on the object is _N. Your Answer: AnswerQuestion 17 (1 point) A girl pulls on a 15 kg wagon at rest with a constant force of 21 N. What is the wagon's acceleration in m/s? Your Answer: Answer Question 18 (1 point) A 18 N falling object encounters 4 N of air resistance. The magnitude of the net force on the object is _ N. Your Answer: Answer Question 19 (1 point) A l kg ball is thrown at 13 m/s straight upward. Neglecting air resistance, the net force that acts on the ball when it is halfway to the top of its path is about _N. Your Answer:Question 28 (1 point) It takes 4 s for a stone to fall to the bottom of a mine shaft. How deep (m) is the shaft? Your Answer: Answer Question 29 (1 point) What is the acceleration ( m/s2 ) of a car that maintains a constant velocity of 90 km/h for 9 s? Your Answer: AnswerA 2,000 kg car experiences a braking force of 10,000 N and skids to a stop in 6 s. The speed of the car just before the brakes were applied was _m/s. Hint: F = m * a a = (change in velocity) / (change in time) Your Answer: Answer Question 11 (1 point) On the surface of Jupiter, where the acceleration due to gravity is about three times that of Earth, a 18 kg rock would have a weight of about _ N. Your Answer: Answer Answer Question 12 (1 point) A car traveling at 49 m/s comes to an abrupt halt in 0. 1 s when it hits a tree. What is the deceleration in meters per second squared of the car? Your Answer:Question 40 (1 point) The force of friction on a sliding object is 17 N. The applied force needed to maintain a constant velocity is N. Your Answer: AnswerQuestion 37 (1 point) If a rocket initially at rest accelerates at a rate of 40 m/s2 for 1 min, its speed will be m/s. Your Answer: Answer Question 38 (1 point) An object is pulled northward with a force of 19 N and northward with a force of 12 N. The magnitude of the net force on the object is N. Your Answer: AnswerQuestion 31 (1 point) A car accelerates at 4 m/s2. Assuming the car starts from rest, how far (m) will it travel in 15 s? Your Answer: Answer Question 32 (1 point) The average speed of a horse that gallops a distance of 35 km in a time of 60 min is km/h. Your Answer: AnswerQuestion 1 (1 point) A 16 kg block with an initial velocity of 12 m/s slides across a horizontal surface and comes to rest. It takes the block 4 s to stop. The stopping force acting on the block is about Your Answer: AnswerQuestion 22 (1 point) An object travels 9 m in the Ist second of travel, 9 m again during the 2nd second of travel, and 9 m again during the 3rd second. Its acceleration is therefore m/$2. Your Answer: Answer Question 23 (1 point) An apple falls from a tree and hits the ground 11 m below. It hits the ground with a speed of about m/s. Hint: First use the distance equation to solve for how long the apple will take fall. Your Answer: Answer Question 24 (1 point) A 280 kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is N. Your Answer:Question 4 (1 point) On the surface of Jupiter, where the acceleration due to gravity is about three times that of Earth, a 8 kg rock would have a mass of about _kg. Your