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3 years ago

10

A car accelerates at a rate of 3 m/s^2. If its original speed is 8 m/s, how many seconds will it take the car to reach a final s

peed of 25 m/s?

1 answer:

kkurt [141]3 years ago

4 0

Answer:

$\Large \boxed{\mathrm{5.67 \ seconds }}$

Explanation:

$\displaystyle \mathrm{acceleration \ = \ \frac{final \ velocity - initial \ velocity }{elapsed \ time}}$

$\displaystyle A \ = \ \frac{V_f - V_i }{t}$

$\displaystyle 3 \ = \ \frac{25 - 8 }{t}$

$\displaystyle 3 \ = \ \frac{17 }{t}$

$\displaystyle t \ = \ \frac{17 }{3} \approx 5.67$

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According to Newton's Third Law of Motion, what happens when two objects of unequal masses collide?

maksim [4K]

<span>Newton's third law is that for every action, there is an equal and opposite reaction.
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B </span>Is just downright wrong. If anything, the smaller mass will be pushed forward with the heavier mass. <span>
C Sounds correct
D It'</span><span>s wrong, because the masses are not equal, or else they would stop.</span>

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3 years ago

At what angle two forces P + Q and (P - Q) act so that their resultant is :

stiv31 [10]

Use resultant formula

$\boxed{\sf R=\sqrt{A^2+B^2+2ABcos\theta}}$

So

#1

A be p+q and B be p-q

$\\ \rm\Rrightarrow R=\sqrt{3p^2+q^2}$

$\\ \rm\Rrightarrow \sqrt{(p+q)^2+(p-q)^2+2(p+q)(p-q)cos\alpha}=\sqrt{3p^2+q^2}$

$\\ \rm\Rrightarrow 2p^2+2q^2+2(p^2-q^2)cos\alpha=3p^2+q^2$

$\\ \rm\Rrightarrow 2cos\alpha=1$

$\\ \rm\Rrightarrow cos\alpha=\dfrac{1}{2}$

$\\ \rm\Rrightarrow \alpha=\dfrac{\pi}{3}$

#2

$\\ \rm\Rrightarrow 2(p^2+q^2)+2(p^2-q^2)cos\beta=2(p^2+q^2)$

$\\ \rm\Rrightarrow 2cos\beta=0$

$\\ \rm\Rrightarrow cos\beta=0$

$\\ \rm\Rrightarrow \beta=\dfrac{\pi}{2}$

#3

$\\ \rm\Rrightarrow 2(p^2+q^2)+2(p^2-q^2)cos\gamma=p^2+q^2$

$\\ \rm\Rrightarrow 2(p^2-q^2)cos\gamma=-(p^2+q^2)$

$\\ \rm\Rrightarrow cos\gamma =\dfrac{q^2-p^2}{2(p^2-q^2)}$

$\\ \rm\Rrightarrow \gamma=cos^{-1}\left(\dfrac{q^2-p^2}{2(p^2+q^2)}\right)$

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2 years ago

Read 2 more answers

How much heat is released when 35kg of water freezes?

inn [45]

You need an additional point of data here: the enthalpy of fusion, or conversely the enthalpy of melting (they differ only by their sign). For water (or ice) that value is gotten from sources such as the internet

<span>ΔH°(fus) = 6.01 kJ/mole </span>

<span>Since you have 35 000g, how many moles do you have? </span>
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<span>So, take that ΔH°(fus) in kJ/mole, multiply by the number of moles, and there ya go!
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3 years ago

A person weighs 60 kg. The area under the foot of the person is 150 cm2. Find the pressure exerted on the ground by the person.

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Answer:

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Explanation:

Applying,

P = F/A................... Equation 1

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From the question,

The force(F) exerted by the person's foot is thesame as it's weight.

F = W = mg............ Equation 2

Where m = mass of the person, g = acceleration due to gravity.

Substitute equation 2 into equation 1

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Substitute these values into equation 3

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Margarita [4]

Answer:

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