Delve AP Physics C Practice Exam #1 Multiple Choice Section 1. Jerk is defined as the rate of change of acceleration with respect to time. What are the SI units of jerk? a) m/s b) m/s 2 c) m/s 3 d) m/s 4 e) m 2. A projectile is fired in the xy-plane at a speed v at an angle of 30 degrees clockwise from the y- axis. Assume gravity points in the -y direction. What is the x-component of the projectile's velocity as a function of time? a) vsin30 b) vcos30 c) v d) vsin30 - gt e) vcos30 - gt 3. For the above scenario, what is the y-component of velocity as a function of time? a) vsin30 b) vcos30 c) v d) vsin30 - gt e) vcos30 - gt 4. Find the magnitude of the sum of the following vectors: <4,6,3> and <0,-3,9>. a) 13 b) 15 c) 12 d) 5 e) 4 5. A wheel rolls forward on a surface without slipping. What point on the wheel experiences the greatest instantaneous velocity? a) The center b) The point on the wheel's circumference directly above the center c) The point on the wheel's circumference directly below the center d) The point on the wheel's circumference directly left or right of the center e) All points experience the same instantaneous velocity 6. Suppose the dot product of two nonzero vectors in the xy-plane, v and w, is zero. Given that v points along the x-axis, which of the following gives all the possible directions of w? a) Along the x-axis b) Along the y-axis c) Along the line y=x d) v or w must be zero
7. Suppose I want to experimentally determine the value of g, the acceleration of gravity. To do this, I drop a ball from rest at some height. Which of the following measurements would give me enough information to calculate g? a) The distance the ball falls and the final velocity of the ball b) The distance the ball falls and the time it takes the ball to fall c) The final velocity of the ball and the time it takes the ball to fall d) All of the above 8. A rod, initially at rest, is given an angular acceleration of 0.5 radians/s 2. After 3 seconds, by what angle has it rotated? a) 1.5 radians b) 3 radians c) 1.25 radians d) 2.25 radians e) 4.5 radians 9. A river's water flows east with velocity u. An observer on the shore sees a swimmer go by with velocity v directed 35 degrees north of east. What is the x-component (east is in the positive x direction) of the velocity of the swimmer with respect to the water? a) vcos35 - u b) vsin35 - u c) vcos35 + u d) vsin35 + u e) u 10. Which of the following forces cannot be decomposed into electromagnetic interactions? a) Weight b) Tension c) Normal Force d) Friction e) Spring Force 11. A spring of force constant k and equilibrium length l is hung from the ceiling. A mass m is hung from the spring and given a small kick so that it oscillates. What is the period of oscillations of this mass? a) k / m b) m/k c) 2 k /m d) 2 m/ k
12. A block rests on an inclined plane. Which of the following would increase the force of friction acting on the block? a) Applying a force on the block perpendicular to the plane b) Moving the plane at a constant velocity c) Increasing the surface area of the block in contact with the plane d) Decreasing the angle of the incline 13. Now suppose the above block is accelerating down the slope. Which of the following would increase the force of friction acting on the block? a) Applying a force on the block perpendicular to the plane b) Moving the plane at a constant velocity c) Increasing the surface area of the block in contact with the plane d) Decreasing the angle of the incline 14. A block of mass 0.2 kg sits on a horizontal surface with coefficient of kinetic friction 0.35. A force of magnitude 5 N is applied to the block at an angle of 45 degrees below the horizontal. What is the acceleration of the block in m/s/s? a) 4.5 b) 7.9 c) 3.3 d) 13.1 e) 0 15. A spring with force constant k is stretched to a length l. You determine that the force exerted by the spring at this length is given by F. What is l 0, the equilibrium length of the spring? a) l b) l - F/k c) F/(k - l) d) F/k - l e) F/k 16. A mass M attached to the end of a rope of length l is whirled around on a table. If the rope will snap if the tension exceeds some value T, what is the maximum angular speed with which the rope may be spun without snapping? a) T /M b) Tl / M c) T / Ml d) Ml e) T/Ml
17. When we describe a wheel as rolling without slipping, what force causes the wheel not to slip? a) Gravity b) Normal Force c) Static Friction d) Kinetic Friction e) Internal Forces within the wheel 18. A force F is applied to a wheel of radius R. The force is directed in towards the center of the wheel. What is the magnitude of the torque created by this force? a) 0 b) F c) RF d) R 2 F e) Depends on the mass of the wheel 19. Suppose a particle moves with a constant speed v for some interval of time. Which of the following must be true? a) The net force on the particle is zero b) The linear momentum of the particle is conserved c) A force is required to keep the particle moving with this speed d) The acceleration of the particle is constant 20. Two figure skaters, both of mass m, stand together on ice (assumed to be a frictionless surface). One skater pushes the other forward, so that she moves with final velocity v. What is the final momentum of the other skater? (With forward defined as positive) a) mv b) -mv c) 0.5mv d) -0.5mv e) 0 21. Angular momentum of a system is conserved if : a) Net force is zero b) Net torque is zero c) Linear momentum is conserved d) Objects are rotating rather than moving in straight lines
22. A cart is initially full of sand and travels with some speed v. The cart has a hole in the bottom, and the sand falls out at a constant rate. At some time later, the cart's speed will be: a) Greater than v b) Less than v c) Equal to v d) Zero 23. A time varying force in the x-direction with magnitude given by F = 2t acts on an object for 10 seconds. What is the change in momentum of this object in the x-direction in kg(m/s)? a) 100 b) 50 c) 25 d) 10 e) 5 24. Suppose we have an object with two forces acting upon it. The forces are equal in magnitude, but opposite in direction. Which of the following statements is true? a) Linear momentum is conserved, angular momentum might situationally be conserved b) Neither linear momentum nor angular momentum is conserved c) Both linear momentum and angular momentum are conserved d) Both linear momentum and angular momentum might be situationally conserved e) Linear momentum is conserved, angular momentum is not conserved 25. A ball of mass m moving with initial speed v collides with a second ball of mass 2m, initially at rest. What is the final velocity of the balls if the collision is completely inelastic? a) v b) 2v c) (1/2)v d) (1/3)v e) 3v 26. Assuming the balls move along the same axis after the collision, what is the direction of the final velocity of the ball of mass m if the collision is perfectly elastic? a) Not applicable the ball is at rest after the collision b) Parallel to the ball's initial velocity c) Anti-parallel to the ball's initial velocity d) The same direction as the final velocity of the ball of mass 2m
27. Two pool balls approach each other along the x-axis on a frictionless table and collide. Which of the following do we know for certain? a) The balls' motion will still be along the x-axis after the collision b) Linear momentum is conserved in both the x and y directions c) The net force on each ball is zero at all times during the collision d) The collision is perfectly elastic e) The collision is inelastic 28. Linear momentum of any given system is (equal in all frames of reference, always zero in the center of mass frame, always conserved, a scalar quantity, none) a) Equal in all frames of reference b) Always zero in the center of mass frame c) Always conserved d) A scalar quantity