Newton’s 2nd Law

May the force be with you.

Fire up a computer. We will be building a powerpoint presentation today.

Standards, 3.1.b,c,d , 3.4.c

Objectives

Students will be able to:

Standards, 3.1.b,c,d , 3.4.c

Solve problems using Newton’s 2nd law of motion.

Newton’s 2nd Law

The following slides contain a problem for each group.

Solve the assigned problem. Create a Powerpoint presentation that

demonstrates the solution.

Standards, 3.1.b,c,d , 3.4.c

Copernicus •  A horizontal cable pulls a 200 kg cart

along a horizontal track. The tension in the cable is 500 N. Starting from rest, how long will it take the cart to reach a speed of 8 m/s? How far will it have gone?

Standards, 3.1.b,c,d , 3.4.c

Newton

•  A 900 kg car is going 20 m/s along a level road. How large a constant retarding force is required to stop it in a distance of 30 m?

Standards, 3.1.b,c,d , 3.4.c

Curie

•  A 12.0 g bullet is accelerated from rest to a speed of 700 m/s as it travels 20 cm in a gun barrel. Assuming the acceleration to be constant, how large was the accelerating force?

Standards, 3.1.b,c,d , 3.4.c

Galileo

•  A 20 kg crate hangs at the end of a long rope. Find its acceleration when the tension in the rope is (a) 250 N, (b)150 N, (c) zero, (d) 196 N.

Standards, 3.1.b,c,d , 3.4.c

Kepler

•  A 5 kg mass hangs at the end of a cord. Find the tension in the cord if the acceleration of the mass is (a) 1.5 m/s² up, (b) 1.5 m/s² down, (c) 9.8 m/s² down.

Standards, 3.1.b,c,d , 3.4.c

Tycho •  A 700 N man stands on a scale on the

floor of an elevator. The scale records the force it exerts on whatever is on it. What is the scale reading if the elevator has an acceleration of (a) 1.8 m/s² up, (b) 1.8 m/s² down, (c) 9.8 m/s² down?

Standards, 3.1.b,c,d , 3.4.c

Einstein

•  What average force is required to stop an 1100 kg car in 8.0 seconds if it is travelling 90 km/h?

Standards, 3.1.b,c,d , 3.4.c

Hawking

•  A 10 kg bucket is lowered by a rope in which there is 63 N of tension. What is the acceleration of the bucket? Is it up or down?

Standards, 3.1.b,c,d , 3.4.c