The Voyager and Pioneer flybys of the 1970s and 1980s provided rough sketches of Saturn’s moons. But during its many years in Saturn orbit, Cassini discovered previously unknown moons, solved mysteries about known ones, studied their interactions with the rings and revealed how sharply different the moons are from one another.

8 0

3 years ago

A crane lifts a load of bricks of weight 20 000 N to a height of 10.0 m. Calculate the work done or energy transferred by the cr

Oxana [17]

Explanation:

here we have mass(m);20 000N in kg will be 9.8kg

acceleration due to gravity (g): 10m/s

height (h) : 10m

so work done will be,

W=mgh

9.8x10x10

980joules

6 0

3 years ago

A smooth circular hoop with a radius of 0.400 m is placed flat on the floor. A 0.325-kg particle slides around the inside edge o

aleksandrvk [35]

Answer:

a) W = - 6.825 J, b) θ = 1.72 revolution

Explanation:

a) In this exercise the work of the friction force is negative and is equal to the variation of the kinetic energy of the particle

W = ΔK

W = K_f - K₀

W = ½ m v_f² - ½ m v₀²

W = ½ 0.325 (5.5² - 8.5²)

W = - 6.825 J

b) find us the coefficient of friction

Let's use Newton's second law

fr = μ N

y-axis (vertical) N-W = 0

fr = μ W

work is defined by

W = F d

the distance traveled in a revolution is

d₀ = 2π r

W = μ mg d₀ = -6.825

μ = $\frac{ -6.825}{d_o \ mg}$

The total work as the object stops the final velocity is zero v_f = 0

W = 0 - ½ m v₀²

W = - ½ 0.325 8.5²

W = - 11.74 J

μ mg d = -11.74

we subtitle the friction coefficient value

( $\frac{-6.8525 }{d_o mg}$ ) m g d = -11.74

6.825 $\frac{d}{d_o}$ = 11.74

d = 11.74/6.825 d₀

d = 1.7201 2π 0.400

d = 4.32 m

this is the total distance traveled, the distance and the angle are related

θ = d / r

θ = 4.32 / 0.40

θ = 10.808 rad

we reduce to revolutions

θ = 10.808 rad (1rev / 2π rad)

θ = 1.72 revolution

3 0

3 years ago