Download presentation

1
Net Force Problems

2
1. An airplane has 4 forces acting on it: weight, drag (air friction), the thrust of the engines and the lift force caused by the flow of air over the wings. 55,000 N 5000 N up If the pilot wishes the airplane to move forward, then the ______ must be greater than the _______. Flift Fdrag 20,000 N Fthrust 20,000 N Airplane Fweight 50,000 N thrust drag

3
**2. A 200 N table has a 30 N book resting upon it.**

Ftable Book Fweight of book 30 N = equal and opposite force of the table pushing up on the book (called the normal force) Book 30 N = mass of book x acceleration (9.81 m/s2)

4
**Each rope must exert a force of 75 N. 150 N = 75 N + 75 N**

3. A child weighing 150 N is sitting on a swing. The swing is equally supported by 2 ropes, one on each side. What is the force exerted by each rope? Each rope must exert a force of 75 N. 150 N = 75 N + 75 N Frope Frope = 75 N, which is the tension force Swing seat Fchild = 150 N, which is the force of weight due to gravity

5
**Fchain 2 = Fweight - Fchain 1 = 1500 N – 600 N = 900 N**

4. Two chains are used to support a small boat weighing 1500 N. One chain has a tension of 600 N. What is the force exerted by the other chain? Fchain 2 = Fweight - Fchain 1 = 1500 N – 600 N = 900 N Fchain 2 Fchain 1 = 600 N Boat Fweight = 1500 N

6
**5. A heavy box weighing 1000 N sits on the floor**

5. A heavy box weighing 1000 N sits on the floor. You press down on the box with a force of 450 N. What is the normal force on the box? (Same method as #4) Fn = 1450 N Box Fp = 450 N Fw = 1000 N A normal force is perpendicular to the plane of action.

7
6. A 40 N cat stands on a chair. If the normal force on each of the cat’s back feet is 12 N, what is the normal force on each front foot? (Same method as #4) The normal force must equal the force of the cat’s weight 40 N = 2(12 N) + 2x 40 N = 24 N + 2x 16 N = 2x 8 N = x Therefore, the normal force on each front foot is 8 N

8
**7. Two forces are acting on a pencil, pushing it to the right**

7. Two forces are acting on a pencil, pushing it to the right. One force is 9 N and the other is 6 N. There is a 6 N force pushing the pencil to the left. What is the net force acting on the pencil? (Don’t forget the direction!) Fp = 9 N Fp = 6 N Pencil Fp = 6 N The net force acting on the pencil is 9 Newtons to the right. Fp = 9 N Pencil

9
**8. A train is climbing a gradual hill**

8. A train is climbing a gradual hill. The weight of the train creates a downhill force of 150,000 N. Friction creates an additional force of 25,000 N acting in the same direction. How much force does the train’s engine need to produce so that the train is in equilibrium (not sliding back down the hill)? Ft = ? N Train Ff = 25,000 N Fw = 150,000 N Ft = Ff + Fw Ft = 25,000 N + 150,000 N = 175,000 N

Similar presentations

OK

Forces and Free Body Diagrams 11/6/13. Bellwork What book did Newton write in 1687? What book did Newton write in 1687? The Principia (Mathematical Principles.

Forces and Free Body Diagrams 11/6/13. Bellwork What book did Newton write in 1687? What book did Newton write in 1687? The Principia (Mathematical Principles.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google