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ad-work [718]
3 years ago
10

Using the standard convention "positive is up", what is the sign of the acceleration of a rock you throw up (a) as it is going u

p, and (b) as it is coming back down?
Physics
1 answer:
Sonbull [250]3 years ago
7 0

Answer:

(a) Negative

(b) Positive

Explanation:

Here is a question on sign.

(a) When the rock is going up, it is working against gravity. In this case, the acceleration due to gravity will take a negative value. This is because gravity works or acts downwards

(b) When the rock is coming down, it is actually working with gravity. So in this case, the sign will ne positive

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Need help with number <br> 50 <br> PLEASE HELP! Show all work please!
Pavel [41]

Answer:50 is b

Explanation:

v = 34757

6 0
3 years ago
How long will it take a person walking at 2.1 m/s to travel 13 m?
MrRissso [65]

Answer:

I gonna give you the number so but you need to round 6.19047619048

Explanation:

  • This is a speed formula so you would use the formula speed=distance/time
  • You need to rearrange it to time=distance/speed
  • So you need to divide 13m by 2.1 m/s

7 0
3 years ago
What is the force on a 15.5 kg ball that is falling freely due to the pull of gravity
velikii [3]

Answer:

151.9 N

Explanation:

Force = mass x acceleration

Acceleration due to gravity is 9.8 m/s^2 (you should memorize this number).

F = ma

F = (15.5)(9.8)

F = 151.9

3 0
3 years ago
A 1600kg cannon fires a 5kg cannonball horizontally. The exit velocity of the cannonball is 80m/s and the barrel length is 2m. W
evablogger [386]

Answer:

 a = 1600 m / s²

Explanation:

For this exercise we use the kinematics relations,

         v² = v₀² + 2 a x

where v₀ is the initial velocity of the bullet, which as part of rest is zero, for the distance (x) we can assume that the gases accelerate along the entire trajectory of the cannon x = 2m

         a = \frac{v^2}{2x}

let's calculate

         a = \frac{80^2}{2 \ 2}

         a = 1600 m / s²

7 0
3 years ago
Astronaut Sarah leaves Earth in a spaceship at a speed of 0.280c relative to Earth. Sarah's destination is a star-system 12.5 li
Usimov [2.4K]

Answer:

L= 12 light years

Explanation:

for length dilation we use the formula

L=L_0\sqrt{1-\frac{v^2}{c^2} }

now calculating Lo

Lo = 12.5×365×24×3600×3×10^8

= 1.183×10^17 m

now putting the values of v and Lo in the above equation we get

L=1.183\times10^{17}\sqrt{1-\frac{0.28c^2}{c^2} }

= 1.136×10^17 m

L=  = \frac{1.136\times10^{17}}{365\times24\times3600\times3\times10^8}m

so L= 12 light years

8 0
3 years ago
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