18. Achild sits on a sled at the top of a hill, the hill makes an angle of 20° with the horizontal. The child's mass is 40kg. Use ps-.1 and 4-.03 a. b. Draw a free body diagram for this system. Does the child accelerate down the hill? *i.e., check that the coefficient of static friction is vercome by the component of the childs weight in the direction the child would accelerate. If they do, what is their acceleration? use coefficient of kinetic friction in sum of the forces balance if the child moves.

18. Achild sits on a sled at the top of a hill, the hill makes an angle of 20° with the horizontal. The child's mass is 40kg. Use ps-.1 and 4-.03 a. b. Draw a free body diagram for this system. Does the child accelerate down the hill? *i.e., check that the coefficient of static friction is vercome by the component of the childs weight in the direction the child would accelerate. If they do, what is their acceleration? use coefficient of kinetic friction in sum of the forces balance if the child moves.

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter6: Applications Of Newton’s Laws Of Motion

Section: Chapter Questions

Problem 9PQ: A man exerts a force of 16.7 N horizontally on a box so that it is at rest in contact with a wall as...

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Review. Three forces acting on an object are given by F1=(2.00i2.00j)N, and F1=(5.00i3.00j)N, and F1=(45.0i)N. The object experiences an acceleration of magnitude 3.75 m/s2. (a) What is the direction of the acceleration? (b) What is the mass of the object? (c) If the object is initially at rest, what is its speed after 10.0 s? (d) What are the velocity components of the object after 10.0 s?
Suppose two children push horizontally, but in exactly opposite directions, on a third child in a wagon. The first child exerts a force of 75.0 N, the second a force of 90.0 N, friction is 12.0 N, and the mass of the third child plus wagon is 23.0 kg. (a) What is the system of interest if the acceleration of the child in the wagon is to be calculated? (b) Draw a free-body diagram, including all forces acting on the system. (c) Calculate the acceleration. (d) What would the acceleration be if friction were 15.0 N?
Commercial airplanes are sometimes pushed out of the passenger loading area by a tractor. (a) An 1800-kg tractor exerts a force of 1.75104 N backward on the pavement, and the system experiences forces resisting motion that total 2400 N. If the acceleration is 0. 150 m/s2, what is the mass of the airplane? (b) Calculate the force exerted by the tractor on the airplane, assuming 2200 N of the friction is experienced by the airplane. (c) Draw two sketches showing the systems of interest used to solve each part, including the free-body diagrams for each.
The driver of a speeding empty truck slams on the brakes and skids to a stop through a distance d. On a second trial, the truck carries a load that doubles its mass. What will now be the trucks skidding distance? (a) 4d (b) 2d (c) 2d (d) d (e) d/2
Consider the baby being weighed in Figure 4.34. (a) What is the mass of the child and basket if a scale reading of 55 N is observed? (b) What is the tension T1 in the cord attaching the baby to the scale? (c) What is the tension T2 in the cord attaching the scale to the ceiling, if the scale has a mass of 0.500 kg? (d) Draw a sketch of the situation indicating the system of interest used to solve each part. The masses of the cords are negligible.
The driver of a speeding empty truck slams on the brakes and skids to a stop through a distance d. On a second trial, the truck carries a load that doubles its mass. What will now be the trucks skidding distance? (a) 4d (b) 2d (c) 2d (d) d (e) d/2
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A young woman buys an inexpensive used car for stock car racing. It can attain highway speed with an acceleration of 8.40 mi/h s. By making changes to its engine, she can increase the net horizontal force on the car by 24.0%. With much less expense, she can remove material from the body of the car to decrease its mass by 24.0%. (a) Which of these two changes, if either, will result in the greater increase in the cars acceleration? (b) If she makes both changes, what acceleration can she attain?
A man exerts a force of 16.7 N horizontally on a box so that it is at rest in contact with a wall as in Figure 6.3. The box weighs 6.52 N. a. Find the static friction force exerted on the box, given the forces being applied, b. If the coefficient of static friction between the wall and the box is 0.50, find the maximum static friction force that may be exerted on the box. Comment on your results.
(a) Find the tension in each cable supporting the 6.00 102-N cat burglar in Figure P4.35. (b) Suppose the horizontal cable were reattached higher up on the wall. Would the tension in the other cables increase, decrease, or stay the same? Why? Figure P4.35
A nurse pushes a cart by exerting a force on the handle at a downward angle 35.0° below the horizontal. The loaded cart has a mass of 28.0 kg, and the force of friction is 60.0 N. (a) Draw a free-body diagram for the system of interest. (b) What force must the nurse exert to move at a constant velocity?
(a) Give an example of different net external forces acting on the same system to produce different accelerations. (b) Give an example of the same net external force acting on systems of different masses, producing different accelerations. (c) What law accurately describes both effects? State it in words and as an equation.