Survey

Survey

Transcript

Exam Review B for grade 12s 1. The initial velocity of a van is 10 m/s [N]. In 4 seconds it accelerates to a velocity of 15 m/s [N]. Calculate the average acceleration. 2. Ms. LateforClass is….late for first period class (wouldn’t dream of being late for Physics) and takes the corner at ND a little too sharply. She accelerates at 2 m/s2 [N40E]. If she accelerates for 3 seconds, and her initial velocity is 5 m/s [N], draw the acceleration vector and determine the final velocity. 3. A Dodge Viper 001 (Special Edition, for Super Spy Agents only) is 40 m behind a Porsche Boxster. The initial speed of the Viper is 25 m/s, and the initial speed of the Boxster is 20 m/s. The driver of the Boxster sees an accident ahead of him (involving a huge PURPLE Dinosaur (wouldn’t know any friendly dinosaurs who lost his tail)) and begins to slow down and has an acceleration of –2 m/s2. What is the speed of the Boxster when the Viper passes by him (assume the speed of the Viper is constant)? 4. A skier starts from rest at the top of a hill (a dangerous slope, the most dangerous slope in all of Brampton….none other than Mt. Chingcousy) and accelerates down it. The coefficient of friction between the skis and the snow is 0.33. The mass of the skier is 50 kg. Draw a diagram and label all the forces acting on the person. Clearly indicate the coordinate system being used in the problem. Determine the final velocity of the skier at the end of the hill, after he has traveled 20 m. Repeat the question for a skier of 75 kg (WHY ARE THE ANSWERS THE SAME?). Do you have to know the mass of the skier to solve the problem? 5. A car (mass is 1000 kg) is rounding a curve, with a bank angle of 20 degrees. The coefficient of friction between the tires of the car and the road is 0.1. The radius of the curve is 100 m. Draw a diagram, complete with all the forces acting on the car, and clearly label the coordinate system. Determine the maximum speed the car can safely take the turn at before it begins to slide. WHY is the answer in the previous question independent of mass (ie. it is the same regardless of the mass of the car). 6. An egg is dropped from a building. Just before the egg hits the ground, it has a velocity of 30 m/s. The egg (mass is 20 grams) comes to a complete stop in 0.2 seconds. Determine the average force acting on the egg during the collision time (of 0.2 seconds) (SOLVE THIS PROBLEM USING IMPULSE). 7. Two billiard balls (each having a mass of 200g) are heading towards each other (see diagram). What does the conservation of momentum state? Is momentum a vector or scalar quanity? Determine the final velocity of ball A after the collision. Is energy conserved? Calculate the total kinetic energy before and after the collision. 18 cm/s time 1: time 2: 30 20 cm/s B B A A 10 cm/s 8. A satellite orbits around the earth. If the orbital period is 9 hours, calculate the altitude of the satellite. 9. A bullet, of mass 5 grams, is fired at a block of wood. The bullet has a speed of 700 m/s. It hits the wood and is embedded within it. If after just hitting the wood, the bullet and wood begin to move with a velocity of 2 m/s, determine the mass of the block of wood. 10. A spring is compressed 0.05 m (spring constant is 3000 N/m) and is then released. A ball (mass is 0.5 kg) is placed in front of the springboard and its initial velocity is 0. time 2: x2 = 0, h2 = 0.6, v2 = ???? time 1: x1 = 0.05, h1 = 0, v1 = 0 0.05 m 0.6 m Determine the speed of the ball at time 2 11. A spring is compressed 0.05 m (spring constant is 3000 N/m) and is then released. A ball (mass is 0.5 kg) is placed in front of the springboard and its initial velocity is 0. Assume the ball loses 0.75 J of energy due to friction time 2: x2 = 0, h2 = 0.6, v2 = ???? time 1: x1 = 0.05, h1 = 0, v1 = 0 0.05 m 0.6 m Determine a) the total energy of the spring-ball system at time 1 b) the total energy of the spring ball system at time 2 c) the kinetic energy of the spring ball system at time 2 d) the speed of the ball at time 2 (WHY IS THIS SPEED LOWER THAN THE PREVIOUS ANSWER in Q. 10) 12. A secret super spy agent is doing some grocery shopping at Fortinos, when he notices a Purple Dinosaur standing at the entrance selling chocolate covered almonds and raising money for the SPD society fund (Save the Purple Dinosaur). Suspicious of the Purple Dinosuar and the fund he represents, the secret super spy agent (who is this secret super spy agent……it is a secret) begins to pull a crate with a force of 50 N, at an angle of 25 degrees to the horizontal, and moves towards the dinosaur. The coefficient of friction is 0.04 (between the crate and the floor). The crate has a mass of 40 kg. He moves the crate a distance of 4 m. Determine the net work done on the crate, the change in kinetic energy of the crate (if initial velocity is 0), the final velocity of the crate. ANTI PURPLE DINO SURPRISE oh yes….its true!!! SPD 25 13. A satellite (mass is 1000 kg) is in orbit 300 kilometers above the surface of the earth ( me = 5.98x1024 kg, re = 6.4x106 m). Draw the diagram. Determine the total energy of the satellite, the kinetic energy of the satellite, the speed of the satellite. 14. Two point charges (q = 1 nanoC, q = 4 nanoC) are separated by a distance of 1 m. Determine the electric field at a point 0.3 m from the 1nanoC charge, the point lying in between the charges (both charges are positive). 15. An oil drop with a negative charge of 1x10-7 C is stationary, between two plates that are parallel to each other. The plates have a potential difference of 200 volts, and are separated by a distance of 1 cm. Draw the diagram (Millikan Oil Drop Experiment, be sure to correctly label the positive and negative plate). Determine the electric field between the plates. Determine the force acting on the oil drop due to electric field. Why is this force the same regardless of the position of the oil drop within the plates? Determine the force of gravity acting on the oil drop. Determine the mass of the oil drop. 16. A charged oil drop is placed in between the plates (see diagram). Upon exiting the plates (dashed circle), the object has moved 5 cm in the x direction. Determine the velocity of the object (both x and y components) as it leaves the plates (consider Fg). y potential difference = 500 Volts x m = 1.5 x 10 -14 kg q = +2.8 x 10 -17C v1 = 0 m/s - + 5 cm 20 cm