PHY 40S WS Zanzibar - Review Questions PDF

PHY 40S WS Zanzibar – Some Review Questions 1. A car initially moving at 20 m/s was found to cover the next 750 m in 30 seconds with uniform acceleration. (A) What was the acceleration of the car? (B) What was the speed of the car at the end of the 30 seconds? 2. A jet going 100 m/s accelerated at...

PHY 40S WS Zanzibar – Some Review Questions 1. A car initially moving at 20 m/s was found to cover the next 750 m in 30 seconds with uniform acceleration. (A) What was the acceleration of the car? (B) What was the speed of the car at the end of the 30 seconds? 2. A jet going 100 m/s accelerated at 8 m/s2 until it was going 180 m/s. (A) How far did it fly in that time? (B) How much time did this take? 3. There is a 20 kg mass on a 20° incline where the coefficient of friction is 0.20. There is a force of 125 N accelerating the mass up the incline. (A) What is the normal force acting on the mass? (B) How much friction is acting on the mass? (C) What is the net force acting on the mass? (D) What is the acceleration of the mass up the incline? 4. A 40 kg mass is initially moving at 5 m/s. A force of 5 N in the direction of motion acts on the mass for 20 seconds. (A) What impulse did the mass receive? (B) What is the final momentum of the mass? (C) What new speed did it have? 5. A 5 kg mass going east at 10 m/s hit head-on with a 15 kg mass going west at 3 m/s. If the two masses hit and stick together, what is their velocity (speed and direction) immediately after impact? 6. Two long parallel current conducting wires are separated by a perpendicular distance of 5 cm. They each carry 3 amperes of current. Each wire is 8 m long. Calculate the force exerted by wire 1 on wire 2. 7. A cannon on a level plain shoots a shell with a speed of 400 m/s at an angle of 20° above the horizontal. (A) For how much time is the shell in the air? (B) How far does it go? (C) How high above the plain did it get? 8. A straight wire has a current of 2.8 amperes. Calculate the magnitude of the magnetic field (in Tesla) at a perpendicular distance of 5 mm from the wire 9. A single circular loop of conducting wire has 5 mA of current flowing through it. If the diameter of the loop is 9 cm, calculate the strength of the magnetic field at the centre of the loop (in Tesla) 10. On a merry-go-round a 25 kg child was made to go around 12 times in 60 seconds. She was 2.0 m from the centre of revolution. (A) What was the period and frequency of her motion? (B) What was her centripetal acceleration? (C) What centripetal force was acting on her? 11. A 40 kg mass is initially moving at 5 m/s on a level, frictionless surface. A force of 20 N applied at an angle of 30° above the horizontal acts on the mass over a distance of 30 m. (A) How much work was done of the mass by the applied force? (B) What new speed did the mass have? 12. A nine cm straight wire carries a current of three Ampere in an external magnetic field of 0.7 Tesla at theta = 41 degrees. Calculate the magnitude of the force felt by the wire. 13. A horizontal spring bumper has spring constant of 200 N/m. It is compressed 40 cm and a 4.0 kg mass is placed against it. The mass is released. (A) How much force did it take to “load” the spring bumper? (B) How much work was done in “loading” the spring? (C)What maximum speed did the mass obtain when it was released? 14. A solenoid has 40 turns along its 20 cm length. If 5 mA of current flow through the solenoid, calculate the magnitude of the magnetic field (in Tesla) at the centre of the solenoid. Also, calculate the turn density , η. 15. The earth has an approximate mass of 6.0x1024 kg and an approximate radius of 6400 km. Consider a 500 kg satellite at an altitude of 22 km above the earth’s surface. What would be its speed and period of orbit? 16. At point A there is a point charge of 4 µC. At point B, which is 30 cm to the right of A, there is a point charge of -6 µC. (A) What is the electric field present at point B? (B) What is the force on the charge at B? (C) What is the electric potential at point A? (D) How much electric potential energy does the system have? (E) How much work would have to be done to increase the separation to 50 cm? (F) What would be the electric field (size and direction) at a point mid-way between the two point charges? 17. Two parallel plates are separated by 4 cm. They have a potential difference of 200 V across them. An alpha particle (+2 ec, 6.67x10-27 kg) is released from rest at the positive plate and accelerates to the negative plate. (A) What is the strength of the electric field between the plates? (B) What is the electric force on the particle? (C) How much work does this electric force do in accelerating the particle from one plate to the other? (D) What is the change in the electric potential energy of the particle as it goes through the potential difference? (E) What is the speed of the particle as it hits the negative plate? 18. A proton has a speed of 4 x 10 4 m/s. It feels a force of 8 x 10 -14 N directed into the paper as it moves north through the magnetic field. Theta = 90 degrees. Calculate both the magnitude and direction of B. 19. A wire that is 25 m long with a diameter of 0.60 mm has resistance of 12 Ω. (A) What is the resistivity of the material? (B) What would be the resistance of a wire of the same material that was 50 m long and had a diameter of 0.30 mm? 20. A boy of mass 60 kg is sitting on a 20 kg sled. If two people are pulling her with two different ropes, find his acceleration. The force applied by person 1 is 40 N [E 30 degrees N] and the force applied by person 2 is 50 N [E 40 degrees S] (neglect friction). 21. A six kg giant pistachio is swung in a vertical circle at 25 m / s. If the string is 1.2 m long, determine the tension in the string at both the top AND bottom of the circle 22. When point A (of charge q) and point B (of charge 2q) are 10 cm apart, the repulsive force between them is 3 x 10-8 newtons. What is the new repulsive force if i) the charge on A is now switched to 3q ? ii) Starting fresh, the distance between A and B is switched to 40 cm. iii) Starting fresh, the charge on A is switched to 5q AND the charge on B is switched to q/2 AND the distance between A and B is switched to 10 mm all at the same time. 23. If the cost of electricity is $0.08 / kWh , how much does it cost to run an electric oven which draws 20 amperes across 240 volts for 4 hours of continuous use ?  ()Loos- t,j F -4 , 3-go h.„ AtT-30.4 ck) v,:aut-04 6(1: V i t tk_dt.2 ;o LI ) vv1 &t '?0 a. 't I at" rrqio- et- 1g '1\42 hx-t4 a-) 11-1 0 0 mi auk ,L,e1 tro / 1.0 -1 I o t. V44,1 ify 0 vitn 3.69 Fh =Is N Ff n 34. g' N (c) E.,21 021.1)N (D) o= I s OL 141/A. 2 i=zp /try Al.4- Pf apA/4" )01314'4 Naf v_r o.o s I. S- xio9 nv ct 5 q s-ryt,  ZJ1HSivt KPc /../02.X/; L( -r- (sx/0-1) -s 9. g -:/.4--NT 7>