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ella [17]
3 years ago
13

You throw a ball straight up with an initial velocity of 15.0 m/s. It passes a tree branch on the way up at a height of 7.00 m.

How much additional time will pass before the ball passes the tree branch on the way back down (in s)?
Physics
1 answer:
Gwar [14]3 years ago
7 0

Answer:

0.95 seconds

Explanation:

t = Time taken

u = Initial velocity = 15 m/s

v = Final velocity

s = Displacement

a = Acceleration = 9.81 m/s² (downward positive, upward negative)

Time taken by the ball to reach the maximum height

v=u+at\\\Rightarrow t=\frac{v-u}{a}\\\Rightarrow t=\frac{0-15}{-9.81}\\\Rightarrow t=1.52\ s

Maximum height

v^2-u^2=2as\\\Rightarrow s=\frac{v^2-u^2}{2a}\\\Rightarrow s=\frac{0^2-15^2}{2\times -9.81}\\\Rightarrow s=11.47\ m

Distance between maximum height of the ball and the branch is 11.47-7 = 4.46 m

So, the distance that will be covered on the way down is 4.46 m

Now

u = 0

s = 4.46

s=ut+\frac{1}{2}at^2\\\Rightarrow 4.46=0\times t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{4.46\times 2}{9.81}}\\\Rightarrow t=0.95\ s

Time taken by the ball from the maximum height to the tree branch is 0.95 seconds.

Total time taken from the moment the ball is thrown to reach the tree branch is 1.52+0.95 = 2.47 seconds

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Answer:

(e) 98,1 KJ

Explanation:

The engine produces 19%; it means, it rejects 81% of energy. ⇒ 81/19=4.26 times.

The engine produces 23 kJ; it means it rejects 23 * 4.26 = 98.05263 kJ

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3 years ago
The distance between a charge and the source of an electric field changes from 3 mm to 6 mm. as a result of the change, the elec
STatiana [176]

The electric potential energy of the charge is reduced because it decreases with increase in the distance between charges.

<h3>What is electric potential energy?</h3>

Electric potential energy can be defined as the energy needed to move a charge against an electric field.

It is calculated using the formula;

U = Kq1 q2 ÷ r

Where Q = electric potential energy

k = Coulombs constant

q1 and q2 = charges

r = distance of separation

Electric potential energy is inversely proportional to the distance of separation of the charges.

If the distance of the charges changes from 3mm to 6mm, then the electric potential energy of the charges is reduced because it decreases with increase in the distance of the charges.

Therefore, the electric potential energy of the charge is reduced because it decreases with increase in the distance between charges.

Learn more about electric potential energy here:

brainly.com/question/14812976

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4 0
2 years ago
North Dakota Electric Company estimates its demand trend line​ (in millions of kilowatt​ hours) to​ be: D​ = 75.0 ​+ 0.45​Q, whe
Alborosie

Answer:

The demand forecast for winter is 96.36 millions KWH

The demand forecast for spring is 145.08 millions KWH

The demand forecast for summer is 169.89 millions KWH

The demand forecast for fall is 73.08 millions KWH

Explanation:

Given that,

The demand trend line​ is

D=(75.0+0.45Q)\times multiplicative\ seasonal\ factors

We need to calculate the demand forecast for winter

Using given formula

D=(75.0+0.45Q)\times multiplicative\ seasonal\ factors

Put the value into the formula

D=(75.0+0.45\times101)\times0.80

D=96.36\ millions\ KWH

We need to calculate the demand forecast for spring

Using given formula

D=(75.0+0.45Q)\times multiplicative\ seasonal\ factors

Put the value into the formula

D=(75.0+0.45\times102)\times1.20

D=145.08\ millions\ KWH

We need to calculate the demand forecast for summer

Using given formula

D=(75.0+0.45Q)\times multiplicative\ seasonal\ factors

Put the value into the formula

D=(75.0+0.45\times103)\times1.40

D=169.89\ millions KWH

We need to calculate the demand forecast for fall

Using given formula

D=(75.0+0.45Q)\times multiplicative\ seasonal\ factors

Put the value into the formula

D=(75.0+0.45\times104)\times0.60

D=73.08\ millions KWH

Hence, The demand forecast for winter is 96.36 millions KWH

The demand forecast for spring is 145.08 millions KWH

The demand forecast for summer is 169.89 millions KWH

The demand forecast for fall is 73.08 millions KWH

3 0
3 years ago
For which question could a testable hypothesis be developed?
Mandarinka [93]
I believe it’s B; Theories may be proven to be true and become laws.
A would make sense if we were talking about hypotheses however, we’re not.
8 0
3 years ago
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