Warm upWarm up

• 1. A 13 kg wagon is pulled is pulled with an 8 N force. The handle makes a 30 degree angle with the horizontal. What is the horizontal acceleration of the wagon?

• 2. When pulled by a rope at a 50 degree angle a 20 kg sled slides across a frictionless surface with an acceleration of 6 m/s2. What is the force pulling the sled?

homeworkhomework

P 151 1-4P 151 1-4

P 169 2-4, 14, 15, 30, 31P 169 2-4, 14, 15, 30, 31

Warm upWarm up• Two wires make a 75 degree

angle with each other. The wires are holding up a 60N street light. What is the tension in each wire?

• How much force will be on each rope if two ropes support a mass at equal angles:

• Mass:200 g– Angles: 15, 30, 45, 60 degrees

• Mass 100 g– Angles: 15, 30, 45, 60 degrees

Inclined Plane ProblemsInclined Plane Problems

• 1. Draw the situation

• 2. Find the Net force in the y direction (perpendicular to the surface)

• 3. Find the Net force in the x direction (parallel to the surface of the plane)

• 4. Find what the problem is asking for

• A 4 kg block is on a frictionless plane which makes a 30 angle with the ground. What is the net force on the block?

ONEONE

• A 7 kg block is on an inclined plane which has a 15 degree slope.

• A. If there is no friction, what is the net force on the block?

• B. What is the block’s acceleration?

• A 3 kg Wood block (μk = 0.2) is on a wooden 2” x 4” tilted at a 50 degree angle. What is:

• A. The gravity force on the block?

• B. The friction force on the block?

• C. The Net Force on the block?

• D. The Acceleration of the block?

TWOTWO

• An 11 kg wood Block is on a wooden ramp set at a 60 degree angle. What are:

• A. The gravity force on the block?

• B. The friction force on the block?

• C. The Net Force on the block?

• D. The Acceleration of the block?

• What force is required to make a 25 kg steel block slide down a 45 degree teflon coated ramp with constant velocity?

HomeworkHomework

P 169 (5, 6, 18, 32, 36, 37)P 169 (5, 6, 18, 32, 36, 37)