Semester: Mac – July 2017Course: PHY440 Mechanics, Waves and Thermal Physics / PHY430 Physics IText books: Jewett, J.W. and Serway, R.A. (2010). Physics for Scientists and Engineers with

Modern Physics, 8th Edition, Brooks/Cole Cengage Learning. Giancoli, D.C. (2009). Physics for Scientists & Engineers with Modern Physics, 4th Edition, Pearson International Edition.

Assignment 1 (Topic 1 – 7)

Question Topic Problem

1 Section 1.3 Dimensional Analysis

No 2 (Softcopy) p.14; No 4 (Hardcopy) p. 14

2. (a) If an equation is dimensionally correct, does that meanthat the equation must be true? (b) If an equation is notdimensionally correct, does that mean that the equationcannot be true?

2 Section 1.4 Conversion of Units

No 15 (Softcopy) p.16; No 13 (Hardcopy) p. 16

A solid piece of lead has a mass of 23.94 g and a volume of2.10 cm3. From these data, calculate the density of lead inSI units (kilograms per cubic meter).

3 Freely Falling Object Lecture 3a Power Point Slides

Example 2-20: Ball thrown upward at edge of cliff.

Suppose that a ball is thrown upward at a speed of 15.0 m/s by a person standing on the edge of a cliff, so that the ball can fall to the base of the cliff 50.0 m below. (a) How long does it take the ball to reach the base of the cliff? (b) What is the total distance traveled by the ball? Ignore air resistance (likely to be significant, so our result is an approximation).

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4 Projectile Motion Lecture 3b Power Point Slides

Example 3-7: A kicked football.

A football is kicked at an angle θ0 = 37.0° with a velocity of 20.0 m/s, as shown. Calculate (a) the maximum height, (b) the time of travel before the football hits the ground, (c) how far away it hits the ground, (d) the velocity vector at the maximum height, and (e) the acceleration vector at maximum height. Assume the ball leaves the foot at ground level, and ignore air resistance and rotation of the ball.

5 Newton’s Laws Lecture 4 Power Point Slides

Example 4-11: Pulling the mystery box.

Suppose a friend asks to examine the 10.0-kg box you were given previously, hoping to guess what is inside; and you respond, “Sure, pull the box over to you.” She then pulls the box by the attached cord along the smooth surface of the table. The magnitude of the force exerted by the person is FP = 40.0 N, and it is exerted at a 30.0° angle as shown. Calculate

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(a) the acceleration of the box, and (b) the magnitude of the upward force FN

exerted by the table on the box.

6 Section 5.8 Forces of Friction

No 44(Softcopy) p.134; No 44 (Hardcopy) p. 134

44. A woman at an airport is towing her 20.0-kg suitcase at constantspeed by pulling on a strap at an angle u above the horizontal (Fig.P5.44). She pulls on the strap with a 35.0-N force, and the frictionforce on the suitcase is 20.0 N. (a) Draw a free-body diagram ofthe suitcase. (b) What angle does the strap make with the horizontal? (c) What is the magnitude of the normal force that the ground exerts on the suitcase?

7 Section 3.4 Components of a Vector and Unit Vectors

No 52 (Softcopy) p.71; No 50 (Hardcopy) p. 71

52. A ferry transports tourists between three islands. It sailsfrom the first island to the second island, 4.76 km away, ina direction 37.0° north of east. It then sails from the secondisland to the third island in a direction 69.0° west of north.

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Finally it returns to the first island, sailing in a direction28.0° east of south. Calculate the distance between(a) the second and third islands and (b) the first and thirdislands.

8 Conceptual Questions No 5 (Softcopy) p.95; No 7 (Hardcopy) p. 95

5. A projectile is launched at some angle to the horizontal with some initial speed vi, and air resistance is negligible.(a) Is the projectile a freely falling body? (b) What is its acceleration in the vertical direction? (c) What is its acceleration in the horizontal direction?

9 Vector: Conceptual Questions

No 2 (Softcopy) p.67; No 4 (Hardcopy) p. 67

2. If the component of vector A along the direction of vectorB is zero, what can you conclude about the two vectors?

10 Vector: Additional Problems No 62 (Softcopy) p.72; No 60 (Hardcopy) p. 72

62. Vectors A and B have equal magnitudes of 5.00 units. The sum of A and B is the vector 6.00 j. Determine the angle between A and B. .

11 Uniform Circular Motion Lecture 5 Power Point Slides

Example 5-12: Revolving ball (vertical circle).A 0.150-kg ball on the end of a 1.10-m-long cord (negligible mass) is swung in a vertical circle. (a) Determine the minimum speed the ball must have at the top of its arc so that the ball continues moving in a circle. (b) Calculate the tension in the cord at the bottom of the arc, assuming the ball is moving at twice the speed of part (a).

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12 Uniform Circular Motion Lecture 5 Power Point Slides

Example 5-13: Conical pendulum.A small ball of mass m, suspended by a cord of length l, revolves in a circle of radius r = l sin θ, where θ is the angle the string makes with the vertical. (a) In what direction is the acceleration of the ball, and what causes the acceleration? (b) Calculate the speed and period (time required for one revolution) of the ball in terms of l, θ, g, and m.

13 Conservation of Energy Lecture 8 Power Point Slides

Conceptual Example 8-5: Speeds on two water slides.

Two water slides at a pool are shaped differently, but start at the same height h. Two riders, Paul and Kathleen, start from rest at the same time on different slides. (a) Which rider, Paul or Kathleen, is traveling

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faster at the bottom? (b) Which rider makes it to the bottom first? Ignore friction and assume both slides have the same path length.

14 Conservation of Energy Lecture 8 Power Point Slides

Example 8-8: Two kinds of potential energy.A ball of mass m = 2.60 kg, starting from rest, falls a vertical distance h = 55.0 cm before striking a vertical coiled spring, which it compresses an amount Y = 15.0 cm. Determine the spring stiffness constant of the spring. Assume the spring has negligible mass, and ignore air resistance. Measure all distances from the point where the ball first touches the uncompressed spring (y = 0 at this point).

15 Energy Conservation with Lecture 8 Power Point Slides

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Dissipative Forces: Solving Problems Example 8-11: Friction with a spring.

A block of mass m sliding along a rough horizontal surface is traveling at a speed v0 when it strikes a massless spring head-on and compresses the spring a maximum distance X. If the spring has stiffness constant k, determine the coefficient of kinetic friction between block and surface.

16 Conservation of Linear Momentum: Inelastic Collisions

Lecture 9 Power Point Slides

Example 9-11: Ballistic pendulum.The ballistic pendulum is a device used to measure the speed of a projectile, such as a bullet. The projectile, of mass m, is fired into a large block of mass M, which is suspended like a pendulum. As a result of the collision, the pendulum and projectile together swing up to a maximum height h. Determine the relationship between the initial horizontal speed of the projectile, v, and the maximum height h.

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17 Additional Problems No 55 (Softcopy) p.273; No 55 (Hardcopy) p. 273

55. A 3.00-kg steel ball strikes a wall with a speed of 10.0 m/s at an angle of = 60.0 with the surface. It bounces off with the same speed and angle (Fig. P9.55). If the ball is in contact with the wall for 0.200 s, what is the average force exerted by the wall on the ball?

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