Have you ever used Mathematica?

What do we want to do today?! Thursday: 2-2-1440 A bit of housekeeping Conclude chapter-7 Introduce chapter-8 Prof. Zain Yamani Office: 15-3100/ 3102; Phone: 860-4363; Mobile: 0504608515 E-Mail: zhyamani@kfupm.edu.sa; HP: http://faculty.kfupm.edu.sa/phys/zhyamani

A bit of housekeeping Attendance If you come late, please make me aware during the (end of) the same lecture.

A bit of housekeeping Mathematica is presumably available in: Building 4/104 Building 7/ 137 Building 66/230 Library

Chapter-7: Energy Kinetic Energy Work Work done by Weight (gravity) Work done by Spring Power

What did we learn about last lecture?

Average and Instantaneous Power P, units of P Pavg Pinstanaeous The horsepower = 746 watt

The tension force is parallel to the incline. A constant tension force is used to pull a 50.0 kg box up a frictionless plane inclined at 30.0° relative to the horizontal. The tension force is parallel to the incline. The box is moved a distance of 30.0 m along the incline with a constant speed of 1.00 m/s. At what rate is work done by the tension force? A) 245 W B) 49.3 W C) 98.0 W D) 292 W E) 495 W 101-2

A 0.50 kg object, moving along the x-axis, experiences the force shown in the Figure. The object’s velocity at x = 0.0 m is v = 2.0 m/s, and at x = 4.0 m is v = 8.0 m/s. What is Fmax? A) 5.0 N B) 7.2 N C) 9.7 N D) 3.2 N E) 1.8 N 101-2

Chapter-7 slides 

Chapter-8: Energy (part-II ) Potential energy (conservative force) Conservation of mechanical energy Reading the potential curve Work done on a system by an external force Conservation of energy

Chapter-8 slides 

Starting from rest, an elevator with a mass of 1 Starting from rest, an elevator with a mass of 1.00×103 kg moves 100 m vertically upward in 50.0 s. At what average rate does the force from the cable do work on the elevator?   A) 19.6 kW B) 11.1 kW C) 29.7 kW D) 31.3 kW E) 15.6 kW 141-2

A 10 kg block is sent up a frictionless ramp along which an x axis extends upward. Figure 4 gives the kinetic energy of the block as a function of position x; the scale of the figure’s vertical axis is set by Ks = 80 J. What is the angle of the inclination of the ramp with respect to the horizontal surface? A) 24 B) 31 C) 19 D) 33 E) 11 141-2

A) They both slide to the same height. A light object and a heavy object are initially sliding with equal speeds along a horizontal frictionless surface. Then, they both slide up the same frictionless incline. Which object rises to a greater height? A) They both slide to the same height. B) The heavy object, because it has greater kinetic energy. C) The light object, because it has smaller kinetic energy. D) The light object, because it weighs less. E) The heavy object, because it weighs more. 101-2

A block is dropped from a high tower and is falling freely under the influence of gravity. Which one of the following statements is true? (Ignore air resistance). A) The kinetic energy increases by equal amounts over equal distances. B) As the block falls, the net work done by all of the forces acting on the block is zero joules. C) The kinetic energy of the block increases by equal amounts in equal times. D) The potential energy of the block decreases by equal amounts in equal times. E) The total energy of the block increases by equal amounts over equal distances. 141-2