Physics C: Mechanics Section I Questions 16-18 The following pairs of equations
ID: 1885818 • Letter: P
Question
Physics C: Mechanics Section I Questions 16-18 The following pairs of equations show how the x- and y-coordinates of a particle vary with time r In the equations, A. B, and a are nonzero constants. Choose the pair of equations that best answers each of the following questions. A choice may be used once, more than once, or not at all 19. A skicr slides at constant speed down a slope (A) X-Acosar y Asinar (B) A cos.r y2A cos.ar inclined at an angle to the horizontal, as shown above. If air resistance is negligible, the coefficient of friction between the skis and the snow is equal to (C) A (C) sin (D) cos (E) tan (E) A 16. Which pair of equations can describe the path of a particle moving with zero acceleration? 20. A 2000 kg car, initially at rest, is accelerated along a horizontal roadway at 3 m/s.What is the average power required to bring the car to a final speed of 20 m/s? 17. Which pair of equations can describe the path of a particle moving with an acceleration that is perpendicular to the velocity of the particle at t0 and remains constant in magnitude and direction? (A) 6 x 103 w (B) 2 x 104 w (C) 3 x 10t w (D) 4 x 10 w (E) 6 x 10t W 18. Which pair of equations can describe the path of a particle that moves with a constant speed und with a nonzero acceleration that is constant in magnitude?Explanation / Answer
16.
since the acceleration is zero . the velocity must be constant
derivative of equations in choice C are constant. hence correct choice is C
20.
vi = initial velocity = 0 m/s
vf = final velocity = 20 m/s
a = acceleration = 3 m/s2
t = time
Using the equation
vf = vi + a t
20 = 0 + 3 t
t = 20/3
work done using wor-change in kinetic energy is given as
W = (0.5) m (vf2 - vi2)
W = (0.5) (2000) (202 - 02)
W = 4 x 105 J
Power is given as
P = W/t
P = (4 x 105)/(20/3)
P = 6 x 104 Watt