Midterm Review - Part 1

Transcription

1 Honor Phyic Fall, 2016 Midterm Review - Part 1 Name: Mr. Leonard Intruction: Complete the following workheet. SHOW ALL OF YOUR WORK. 1. Determine whether each tatement i True or Fale. If the tatement i fale, correct the tatement o that it i true. (a) It i not poible to explain the Law in Chemitry and Biology term of the Law of Phyic. (b) Claical Phyic decribe the advancement that were made in the field of Phyic before publication of Iac Newton Principia in (c) Theorie and law in Phyic may change if experiment, conducted by everal group, how a reproducible reult which contradict the prediction of the theory or law. (d) A theory i what you viualize in your head when tudying a phenomenon you can not directly oberve, uch a the interaction between light and the electron in an atom. (e) It i impoible for a meaurement to have high preciion and low accuracy. (f) The SI unit of ma i the gram. (g) When an object i thrown into the air, and return to it initial height. The object pend the ame amount of time traveling upward a it doe traveling downward. (h) When an object i thrown vertically upward into the air, the object acceleration i momentarily zero when the object reache the top of it trajectory. ( i) Negative acceleration alway tend to decreae the peed of an object. (j) A car driving at a contant peed a it goe around a bend experience an acceleration becaue the direction of the car motion change.

2 Honor Phyic/Midterm Review - Part 1 Page 2 of 13 Name: 2. Determine the number of ignificant figure in each value. (a) 3.0 m (b) kg (c) Convert the following into the correponding bae unit in SI. (a) 2.0 ( 10 2) g (b) 1.2 n (c) 3.2 km min (d) 1.0 mm 2

3 Honor Phyic/Midterm Review - Part 1 Page 3 of 13 Name: 4. A Realtor meaure the area of a room. He meaure the length to be m with an uncertainty of ±2 cm and the width to be 8.00 m with an uncertainty of ±1 cm. (a) What i the percent uncertainty in the meaurement of the meaured length and width? (b) What i the uncertainty in the area meaured in quare meter? 5. Ue the figure below to anwer part (a) through (d). C D A B E F G H (a) E + H = (b) F E = (c) G + H = (d) E + F + G + H =

4 Honor Phyic/Midterm Review - Part 1 Page 4 of 13 Name: 6. After a day of hiking, you and a friend decide to top and etup camp. Since you don t want to camp right next to the trail, you and your friend decide to plit up in earch of a good camping pot. After walking 1 mile Wet, your fiend call you and tell you that he found an excellent pot under a large overhang. Your fiend tell you that he found the pot by walking 1 mile, in a direction 30 North of Eat from the trail. (a) Uing the pace below, draw a vector, A, which repreent your diplacement. Starting from the the tail of vector A, draw a vector, B, which repreent the diplacement of your friend. Finally, draw a vector, C, which how the path you would need to follow to meet up with your friend. Label all three vector. N E (b) How are the vector, A, B, C related? (I am looking for a mathematical expreion involving A, B, and C.) (c) Calculate the component of A (uing component along the North-South direction and the Eat- Wet direction). (d) Calculate the component of B. (e) Calculate the component of C. (f) Auming you walk in a traight line, determine how far you would need to walk to meet up with your friend. (g) In what direction hould you walk o that you will meet up with her?

5 Honor Phyic/Midterm Review - Part 1 Page 5 of 13 Name: 7. The graph below how the velocity of an object a a function of time. ( m ) v t () (a) What i the acceleration hown in the graph above? (b) How far doe the object travel between t 0 = 0.0 and t f = 5.0? 8. A runner accelerate to a velocity of 4.15 m in Hi average acceleration i a avg = m 2. What wa hi velocity when he began accelerating? 9. In getting ready to do a lam-dunk, a baketball player tart from ret and print to a peed of 6.0 m in Auming that the player accelerate at a contant rate, determine the ditance he run.

6 Honor Phyic/Midterm Review - Part 1 Page 6 of 13 Name: 10. A peed kater i traveling at 8 m. The kater hit a 5.0 m wide rough patch of ice and decide to low down. She leave the rough patch moving at 6 m. Auming the kater acceleration i contant, what wa her acceleration when kating over the rough patch of ice? 11. A rifle i aimed horizontally at a target that i 50 m away. The bullet hit the target 2.0 cm below the point where the rifle wa aimed. How fat wa the bullet moving when it left the barrel of the rifle?

7 Honor Phyic/Midterm Review - Part 1 Page 7 of 13 Name: 12. You kick a occer ball giving it an initial velocity of 20 m at and angle of 30 above the horizontal. (a) What are the horizontal and vertical component of the initial velocity. (b) What are the horizontal and vertical component of the velocity when the ball reache it maximum height? (c) How long doe it take for the ball to reach it maximum height? (d) What i the maximum height achieved by the ball? (e) How far doe the ball travel, in the horizontal direction, before hitting the ground? (f) How fat i the ball traveling the intant before hitting the ground?

8 Honor Phyic/Midterm Review - Part 1 Page 8 of 13 SOLUTIONS Solution to Midterm Review - Part 1 1. (a) Fale. Phyic i the mot fundamental cience. All baic cience can be explained in term of Phyic. 1. (b) Fale. Claical Phyic decribe the advancement that were made in the field of Phyic prior to the dicoverie of the atom, Eintein Theory of Relativity, and Quantum Mechanic. Thee dicoverie occurred during the late nineteenth and early twentieth centurie. 1. (c) True. 1. (d) Fale. A model i what you viualize. 1. (e) Fale. Preciion decribe how reproducible a meaurement i, while accuracy decribe how well it agree with the expected reult. A highly reproducible meaurement which diagree with the expected value ha high preciion by low accuracy. 1. (f) Fale. the SI unit of ma i the kilogram. 1. (g) True. 1. (h) Fale. The object velocity i momentarily zero. The acceleration i alway 9.8 m (i) Fale. An object dropped from ret peed up a it accelerate toward the ground. However, if we define up a the poitive direction and down a the negative direction, the acceleration of the object will be negative. 1. (j) True. 2. (a) Zero which are to the right of the decimal place and which occur after the firt non-zero digit are ignificant. So, 3.0 ha 2 ignificant figure. 2. (b) The two leading zero not ignificant. However, the zero between non-zero number i ignificant. So, ha 3 ignificant figure. 2. (c) The firt three zero are not ignificant becaue they occur before the firt non-zero digit. The zero at the end i ignificant becaue it: occur after the firt non-zero digit & appear to the right of the decimal place. So, ha 2 ignificant figure. 3. (a) 3. (b) 3. (c) 3. (d) 3.2 km min 2.0 ( 10 2) ( ) 1 kg g = 0.2 kg 1000 g 1.2 n ( 10 9 ) = 1.2(10 9 ) 1 n ( 1000 m 1 km ) ( 1 min ) = m 60 ( ) m mm 2 = 1.0 ( ) m 2 mm 4. (a) When calculating the percent uncertainty, we mut ue the ame unit for the uncertainty and the meaured value. Therefore, we mut convert the uncertainty into meter when we plug it into the

9 Honor Phyic/Midterm Review - Part 1 Page 9 of 13 SOLUTIONS formula for the percent uncertainty. ( ( ) ) m Percent Uncertainty = 100% m = 0.2% For the width we get: ( ( ) ) m Percent Uncertainty = 100% 8 m = 0.125% 4. (b) The percent uncertainty in the area i given by the Method of Adding Percent Error: 0.2% % = 0.325%. The meaured area i: (10 m) (8 m) = 80 m 2. Uing the percent uncertainty formula to olve for the uncertainty in the meaured area give: ( ) δx Percent Uncertainty = 100% x ( ) Percent Uncertainty δx = x 100% ( ) 0.325% = 80 m 2 100% = 0.26 m 2 5. (a) B 5. (b) A 5. (c) D 5. (d) 0 6. (a) N E A C B 6. (b) Firt you need to undo what you did when you walked one mile wet, which i accomplihed with a A. Then you need to walk one mile 30 North of Eat, which i B. So,

10 Honor Phyic/Midterm Review - Part 1 Page 10 of 13 SOLUTIONS C = B A 6. (c) For thi problem Eat will be the poitive x direction while North will be poitive y direction. Since you walked Wet, the x component of you diplacement i 1.0 mile, while the y component of your diplacement i zero mile. In other word: A x = 1.0 mile, A y = 0.0 mile. 6. (d) To find the x and y component of B we will need to ue trigonometry. B 30 B y B x A we can ee from the figure above, B x = (1.0 mile) co(30 ) = mile and B y = (1.0 mile) in(30 ) = 0.5 mile. 6. (e) In part (b) we found that C = B A. To find the x component of C all we need to do i apply thi equation to the x component of A and B. Looking at the y component give: C x = B x A x = mile ( 1.0 mile) = mile C y = B y A y = 0.5 mile 0 mile = 0.5 mile 6. (f) To find the ditance we need to walk, all we need to do i calculate the magnitude of C. C = Cx 2 + Cy 2 = 1.93 mile 6. (g) To find the direction of C we ue arctangent. N E θ C x C C y ( ) 0.5 mile θ = arctan mile = 15 North of Eat

11 Honor Phyic/Midterm Review - Part 1 Page 11 of 13 SOLUTIONS 7. (a) Recall that the lope of a velocity veru time graph give you the acceleration. Uing any two point on thi graph, we can calculate the lope, and therefore the acceleration. a = v t = 3.0 m 5.0 = 0.6 m 2 7. (b) From thi graph we can ee that the initial velocity i 1.0 m. We alo found the acceleration to be 0.6 m 2. Uing x = 1 2 a ( t)2 + v 0 t we can calculate x. x = 1 2 a ( t)2 + v 0 t (0.6 m 2 ) (5.0 ) 2 + = 1 2 = 12.5 m ( 1.0 m ) (5.0 ) 8. Once again we tart by writing down all the quantitie we know and need to know. v = 4.15 m a avg = m 2 t = 1.50 All we need to do to olve thi problem i apply the definition of average acceleration: a avg = v t a t = v f v 0 v 0 = v f a t = 4.15 m (0.64 m )(1.5 ) 2 = 3.19 m 9. Once again we tart by writing down all the quantitie we know and need to know. v 0 = 0 m v f = 6 m t = 1.5 The firt tep in olving thi problem i to calculate the player acceleration: a = v t = 6 m 1.5 = 4.0 m 2 From thi point we can proceed two way: uing x = 1 2 a t2 + v 0 t or v 2 f = v a x.

12 Honor Phyic/Midterm Review - Part 1 Page 12 of 13 SOLUTIONS I ve choen to ue the former, however you hould get he ame anwer regardle of which equation you chooe (in fact thi i an excellent way to check your anwer). x = 1 2 a t2 + v 0 t = 1 ( 4 m ) ( ) = 36 8 m = 4.5 m 10. Start by writing down all the quantitie we know and need to know. v 0 = 8 m v f = 6 m x = 5 m a =? Since we know the initial and final velocitie and were not given t, we hould ue vf 2 = v a x to olve for a. v 2 f = v a x a = v2 f v2 0 2 x = 2.8 m Start by writing down the known and unknown quantitie. x = 50 m v y,0 = 0 m y = 0.2 m v x =? We are told that the bullet travel 50 m in the x-direction in the ame time it take for the bullet for fall 20 cm in the y-direction. To find v x we will ue v x = x. Since we know x, all we need to do i t find t. To find t, we ue the y-component of the motion. y = 1 2 a y ( t) v 0 t ( t) 2 = 2 y g 2 y t = g Plugging thi into v x = x t give: v x = 783 m. = 6.39 (10 2 )