2 years ago

If a girl is standing still and holding a box, is she doing any work? (No)

Physics

2 answers:

SpyIntel [72]2 years ago

7 0

Answer:

gravity

Explanation:

maxonik [38]2 years ago

6 0

The gravity on the box is not the same force as the movement

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A 60kg block rests on rough horizontal ground. A rope is

ANTONII [103]

Answer:

Explanation:

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2 years ago

A pulse traveled the length of a stretched spring the pulse transferred...A)energy only B)mass only C)both energy and mass D) ne

xz_007 [3.2K]

Answer:

Explanation:

So a pulse is a part of a mechanical wave, and mechanical waves are energy transfer trough some medium, in this case a stretched spring. So the correct answer is (A) energy only. The pulse cant be transferred into mass.

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2 years ago

A projectile is launched with an initial velocity of 25m/s at 35 degrees above the horizontal. assuming that the projectile retu

Dovator [93]

Speed is the same as the initial: 25m/s.

*if* you need vectors though:

final velocity = (25*cos(35), -25*sin(35) ) m/s

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2 years ago

C) A sample of substance of volume 10 cm3 was brought back to Earth from the Moon.

postnew [5]

Answer:

8125

Explanation:

$P=0,13 N\\a=1,6 N/kg\\m=P/a=0,13/1,6=0,08125\\V=10(cm)^{3} =10^{-5} meters^{3} \\p=m/V=0,08125/10^{-5} =0,08125*100000=8125kg/meters^{3}$

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3 years ago

An object moves uniformly around a circular path of radius 19.0 cm, making one complete revolution every 2.40 s.

klio [65]

Answer:

v = 0.5 m/s

f = 0.42 Hz

ω = 2.6 rad/sec

Explanation:

By definition, the translational speed is the rate of change of the position with respect to time.
The change in position along a complete revolution is just the following:
Δs = 2*π*r = 2*π*0.19 m = 1.19 m
The time needed to complete a revolution is 2.4 s, so the translational speed can be written as follows:

$v =\frac{\Delta s}{\Delta t} = \frac{1.19m}{2.4s} = 0.5 m/s (1)$

The frequency in Hz is just the inverse of the time needed to complete a revolution (known as the period T), as follows:
f = 1/T = 1/2.4s = 0.42 Hz (2)
Finally, the angular speed is the rate of change of the angle rotated with respect to time, as follows:

$\omega = \frac{\Delta\theta}{\Delta t} = \frac{2*\pi}{2.4s} = 2.6 rad/sec (3)$

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3 years ago