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6/8/23, 6:17 PM The Expert TA | Human-like Grading, Automated! [23 Summer I] PHYS270 2 Magnetic forces & Torques Problem 1: A negative charge of g =-6.8 X 10°17C and m = 6.7 x 1026 kg enters a magnetic field B = 0.35 T with initial velocity v = 770 m/s, as shown in the figure. The magnetic field points into the screen. X X X X X X X Randomized Variables o Y > X X X X X X X g=-6.8x10"1"C m=6.7x 1026 kg B 0351 X X X X X X X v=770 m/s X X X X X X X ©theexpertta.com Part (a) Which direction will the magnetic force be on the charge? MultipleChoice : 1) To the right. 2) Out of the screen. 3) Into the screen. 4) To the left. 5) Upward. 6) Downward. Part (b) Express the magnitude of the magnetic force, F, in terms of ¢, v, and B. Expression : F= Select from the variables below to write your expression. Note that all variables may not be required. u’ B’ 0’ |q|’ a’ B’ d’ F’ g’ h’ i’ P’ r’ t’ v Part (c) Calculate the magnitude of the force F, in newtons. Numeric : A numeric value is expected and not an expression. F= Part (d) Under such a magnetic force, which kind of motion will the charge undergo? MultipleChoice : 1) Variable linear motion. 2) Uniform linear motion. 3) Uniform circular motion. Part (e) Express the centripetal acceleration of the particle in terms of the force F and the mass m. Expression : a = Select from the variables below to write your expression. Note that all variables may not be required. a’ B’ 0’ |q|’ a’ B, d" F’ g’ h’ i’ j’ k’ m’ P’ q’ r’ R’ t, v Part (f) Calculate the magnitude of a, in meters per square second. Numeric : A numeric value is expected and not an expression. a = Part (g) Express the radius, R, of the circular motion in terms of the centripetal acceleration a and the speed v. Expression : R= Select from the variables below to write your expression. Note that all variables may not be required. B.06,a,B,d,F,g.h,imn P,q,¢tv https://ush22md.theexpertta.com/Common/ViewAssignmentDetails.aspx 1/5

6/8/23, 6:17 PM The Expert TA | Human-like Grading, Automated! Part (h) Calculate the numerical value of the radius R, in meters. Numeric : A numeric value is expected and not an expression. R = Problem 2: A proton is moving with a velocity of v = Vel + 'vyj, where vx = 92 m/s and vy = 69 m/s. The proton enters a magnetic field B = Byj, where By = 4.8 T. fi Y ok > z Part (a) Express the magnetic force F in terms of the proton charge e, velocity v and the magnetic field B. SchematicChoice — — — e F|=et-B F=etxB |F|=e¢B-¥ — — F=eB xv Part (b) For this particular case, express the magnitude of the force, F', in terms of e, vy, vy, and By. Expression F = Select from the variables below to write your expression. Note that all variables may not be required. By, e, g, m, vy, vy Part (c) Calculate the numerical value of F' in newtons. Numeric : A numeric value is expected and not an expression. F = N Part (d) What is the direction of the force F? MultipleChoice 1) Positive z direction. 2) Negative x direction. 3) Negative z direction. 4) Negative y direction. 5) Positive y direction. 6) Positive x direction. https://ush22md.theexpertta.com/Common/ViewAssignmentDetails.aspx ©theexpertta.com 2/5

6/8/23, 6:17 PM The Expert TA | Human-like Grading, Automated! Problem 5: A rectangular loop with L; =0.35 mand L, = (.75 m is sitting in a magnetic field B = 0.15 T as shown in the figure. There is a counterclockwise current 7= E‘ e I : a L d 0.25 A in the loop. i % I — Ly : ~ Ly _ > | | . [ b —> | f ©theexpertta.com Part (a) Express the magnitude of the magnetic force on ab or cd, F;, in terms of the length L, current / and magnetic field B. Expression : F 1= Select from the variables below to write your expression. Note that all variables may not be required. o, B’ n, 05 B’ d: Fl’ g, h: Ia Ll’ L2’ m, Pa t Part (b) Calculate the numerical value of the magnitude of the force, F;, on ab or cd in N. Numeric : A numeric value is expected and not an expression. F 1= Part (c) Express the magnitude of the magnetic force on bc or ad, F'», in terms of the length L, current / and magnetic field B. Expression : F2 = Select from the variables below to write your expression. Note that all variables may not be required. a, B’ n, e’ B’ dy FI’ g h, Ia Ll, L25 m, P7 t Part (d) Which direction does the force on ab act? MultipleChoice : 1) To the right. 2) Upward. 3) Downward. 4) Into the screen. 5) Out of the screen. 6) To the left. Part (e¢) Which direction does the force on cd act? MultipleChoice : 1) To the left. 2) To the right. 3) Upward. 4) Out of the screen. 5) Into the screen. 6) Downward. Part (f) Express the torque of F'; on ab, with respect of the axis ef, in terms of F; and L,. Expression : Tab ™~ Select from the variables below to write your expression. Note that all variables may not be required. o, B: n, 0’ B: d: Fl’ g, h: I: Ll’ L2: m, P: t Part (g) Express the torque of F; on cd, with respect of the axis ef, in terms of F; and L. Expression : Ted = Select from the variables below to write your expression. Note that all variables may not be required. https://ush22md.theexpertta.com/Common/ViewAssignmentDetails.aspx 4/5

6/8/23, 6:17 PM The Expert TA | Human-like Grading, Automated! aa Ba n; 05 Ba d: Fl) ga h, I5 Lla L2: m: P9 t Part (h) What is the total torque on the current loop with respect of axis ef, in terms of F; and L,? Expression T = Select from the variables below to write your expression. Note that all variables may not be required. o, Ba n, 03 Ba d: Fla g, h’ I: L]a L2: m, P: t Part (i) Calculate the numerical value of the total torque in N-m. Numeric : A numeric value is expected and not an expression. T = Part (j) Express the torque of F; on ab, with respect of the axis cd, in terms of F; and L. Expression Ted ™ Select from the variables below to write your expression. Note that all variables may not be required. a, B: n, 0, B: d’ Fl: g, h:« Ia Ll: LZ’ m, P’ t Part (k) Express the torque of F; on cd, with respect of the axis cd, in terms of F; and L,. Expression Ted ™~ Select from the variables below to write your expression. Note that all variables may not be required. (l, B’ fl:, 0’ B’ d, FI’ g: h, Ia Ll’ L2, m, P: t Part (I) What is the total torque on the current loop, with respect of the axis cd, in terms of F; and L,? Expression T = Select from the variables below to write your expression. Note that all variables may not be required. a, B: n, 0, B: d’ Fl, g, h’ Ia Ll: L2’ m, P: t Part (m) True or false: the total torque on the loop is the same regardless of what is chosen as the position of the vertical axis of rotation. TrueOrFalse : 1) 2) All content © 2023 Expert TA, LLC https://ush22md.theexpertta.com/Common/ViewAssignmentDetails.aspx 5/5