Question

Gina pushes a book across a table at a constant speed. Fatima lowers a book from a high shelf down to her waist, where it comes to rest. Isidra holds a book at her waist while carrying it up the stairs. Jin holds a book at her waist while carrying it across the room at constant speed. Who does zero work on their book?

A. Gina

B. Fatima

C. Isidra

D. Jin

An oscillator undergoes simple harmonic motion described by the equation of x = (2.0 cm) ∙ sin (4.4 s-1 ∙ t). What's this oscillator's period?

A. 4.4 s

B. 1.4 s

C. 0.23 s

D. 0.71 s

Which of the following would not affect the period of a simple harmonic oscillator?

A. changing a pendulum's length

B. changing the mass attached to a spring

C. changing the amplitude of oscillations

D. changing out the spring while keeping the same mass

Answer 1

here,

1)

W = F * s * cos(theta)

for zero work done

the angle between the force applied and displacement must be 90 degree

so, the zero work done is for D) Jin

2)

x = ( 2 cm) sin(4.4 s^-1 * t)

the angular speed , w = 4.4 rad/s

the oscillation period , T = 2pi/w

T = 2*pi /4.4 s

T = 1.4 s

the oscillation's period is B) 1.4 s

3)

time period of spring , T = sqrt(K/m)

when the spring is changed

the spring constant changes

and the time period also changes

so, the correct option is D)changing out the spring while keeping the same mass