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2 years ago

As a projectile moves down its vertical velocity is positive?

1 answer:

7 0

When YOU start working on a problem, if the question doesn't TELL you which direction is positive and which is negative, then YOU get to decide before you start solving the problem.

MOST often, people use positive for UP and negative for DOWN, just because that's the way we naturally think of 'up' and 'down'. But there's no law. If you want to, you can just as well call up 'negative' and call down 'positive'.

You might be interested in

The frequency of the second harmonic of a certain musical instrument is 100 Hz. What is the fundamental frequency of the instrum

ruslelena [56]

The harmonic frequency of a musical instrument is the minimum frequency at which a string that is fixed at both ends in the instrument may vibrate. The harmonic frequency is known as the first harmonic. Each subsequent harmonic has a frequency equal to:
n*f, where n is the number of the harmonic and f is the harmonic frequency. Therefore, the harmonic frequency may be calculated using:
f = 100 / 2
f = 50 Hz

4 0

2 years ago

An object has a kinetic energy of 175 J and a momentum of magnitude 25.0 kg m/s. Find the

DedPeter [7]

Answer:14 m/s

Explanation:

Kinetic energy(ke)=175J

Momentum(M)=25kgm/s

Speed=v

Mass=m

Ke=(m x v x v)/2

175=(mv^2)/2

Cross multiply

175 x 2=mv^2

350=mv^2

Momentum=mass x velocity

25=mv

m=25/v

Substitute m=25/v in 350=mv^2

350=25/v x v^2

350=25v^2/v

v^2/v=v

350=25v

v=350/25

v=14 m/s

5 0

3 years ago

If no heat is lost to the surroundings, how much heat must be added to raise the temperature from 20.0 ∘C to 85.0 ∘C ?

andrey2020 [161]

Answer:

Explanation:

$C_{water}$ = 4190 J/kg.K

$C_{Al}$ = 910 J/Kg. K

$m_{Al}$ = 1.50 kg

$m_{water}$ = 1.80 kg

$Q_{added} = Q_{Al} + Q_{water}$

$=m_{Al} C_{Al}$ ΔT + $m_{water} C_{water}$ ΔT

= (1.50)(910)(85.0-20)+(1.80)(4190)(85.0-20)

= 578,955 J

= 579 kJ

3 0

3 years ago

Imagine a Rip-van-Winkle type who lives in the mountains. Just before going to sleep he yells "WAKE UP" and the sound echoes off

stiv31 [10]

Answer:

4939200 m

Explanation:

v = Velocity of sound in air = 343 m/s (general value)

For the echo to reach Rip van Winkle it must cover the distance to the mountain twice. So, time taken for the sound traveling to the mountain once

$t=\dfrac{8}{2}=4\ hr$

Distance is given by

$s=vt\\\Rightarrow s=343\times 4\times 60\times 60\\\Rightarrow s=4939200\ m=4939.2\ km$

The distance to the mountain is 4939200 m

6 0

3 years ago

A shallow groove on the surface of the cortex is called a ________.

Juli2301 [7.4K]

Answer:

sulcus

Explanation:

A sulcus is an indentation or depression in the brain that causes it to look like it ridges or folds

Cerebral sulci and fissures are grooves between the adjacent gyri on the surface of the cerebral hemispheres.

Sulci can be basically can be divided into three basic function

limiting sulcus: This happens to develop between areas differing in structure and function, for example central sulcus

axial sulcus: This develops along the axis of a rapidly growing/developing area (e.g. calcarine sulcus)

operculated sulcus: a sulcus may be between two structurally-different areas and a third sulcus may lie in its wall and does not appear on the surface (e.g. lunate sulcus)

3 0

3 years ago