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andrew11 [14]
3 years ago
13

A rock is thrown straight downward from a tree limb with an initial velocity v0. The rock has constant downward acceleration of

10 m/s2 during its fall. The rock moves 7 times as far during the first 3 seconds as during the first 1 second of fall. What is the value (magnitude only) of v0?
Physics
1 answer:
viktelen [127]3 years ago
3 0

Answer:

v₀ = 15 m/s

Explanation:

given,

initial velocity = v₀

down acceleration of rock = 10 m/s²

rock distance

  S₄ = 7 x S₁

From kinematic equations

S = v₀ t+0.5 at²

at t = 1 s

S₁ = v₀ (1)+0.5 x 10 x 1²

S₁ = v₀+ 5......(1)

at t = 4 s

 S₄ = v₀ (4)+0.5 x 10 x 4²

 S₄ = 4 v₀+80.....(2)

from equation (1) and  (2)  

7( v₀ + 5 ) = 4 v₀ +80

3 v₀ = 80 - 35

3 v₀ = 45

v₀ = 15 m/s

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Answer:

3.) 463 J/g

Explanation:

Heat given by the fuel is used to increase the temperature of the water

so it is given as

Q = ms\Delta T

here we will have

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now we also know that

s = 4186

so we have

Q = (0.250)(4186)(26.55 - 25)

Q = 1622.075 J

so 3.5 g fuel gives above energy

so per gram of fuel will have total energy given as

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6 0
3 years ago
If a high jumper needs to make his center of gravity rise 1.50 m, how fast must he be able to sprint? Assume all of his kinetic
sergiy2304 [10]

Answer:

v = 5.42 m/s

Explanation:

given,

height of the jumper = 1.5 m

velocity of sprinter = ?

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g h = \dfrac{1}{2}v^2

v =\sqrt{2gh}

v =\sqrt{2\times 9.8 \times 1.5}

v = 5.42 m/s

Speed of the sprinter is equal to v = 5.42 m/s

7 0
3 years ago
Einstein’s general theory of relativity made or allowed us to make predictions about the outcome of several experiments that had
PtichkaEL [24]

Answer:

1. bending of light in gravitational fields.

2. effect of gravitational redshift.

3. perihelion precission of mecury.

Explanation:

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3 years ago
On the basis of which characteristics jute is considerd as a natural fibre​
klemol [59]

Answer:

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6 0
3 years ago
A line of dominos is knocked down. Which explanation is true?
Llana [10]

B: an increase in acceleration caused an increase in force.

This is based on the concept of force on an object.

Now, formula for force is commonly known as;

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Now, mass and acceleration are the input values that make the output which is the Force to either increase or decrease.

  • Now, for the line of dominoes to fall, it means that the force was so overwhelming that the dominoes couldn't resist it.

Now, this output which is the force became so much as a result of the increase in acceleration of the motion that triggered its movement.

Moreover, the force is directly proportional to the acceleration!

Thus, we can say that an increase in acceleration caused an increase in force.

Read more at; brainly.in/question/25954363

4 0
3 years ago
Read 2 more answers
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