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zhannawk [14.2K]

4 years ago

8

physics a flower pot falls from a windowsill 25.0m above the sidewalk. how much time does a passerby on the sidewalk below have

to move out of the way before the flowerpot hits the ground? i need help!!! i suck at physics

1 answer:

Usimov [2.4K]4 years ago

8 0

$v_f^2 = v_0^2 + 2*a*d$
Since the flower pot is dropped, it has an initial velocity of zero. Also the flower pot accelerates due to gravity.

so

$v_f = \sqrt{2*g*d}=\sqrt{2*9.81*25.0}$

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A small asteroid with a mass of 1500 kg moves near the earth. At a particular instant the asteroid’s velocity is ⟨3.5 × 104, −1.

zalisa [80]

Answer:

$P_{f}$ =(5.7 x $10^{7$ i - 2.24 x $10^{7$ j) kgm/s

Explanation:

Due to earths gravity, force on asteroid is given by:

$F= \frac{Gm_{1}m_{2} }{r^{2} }$ r^

Plugging in the values, we have

F= [(6.67x $10^{-11}$ )(1500)(5.97 x $10^{24}$ )(8x $10^{6}$ i + 9x $10^{6$ j)] / ((8x $10^{6}$ )² + (9x $10^{6$ )² $)^{1.5}$

F= 2736 i^ + 3078 j^

In order find the final momentum of the Asteroid, apply impulse momentum theorem

$P_{f}$ = $P_{i$ + FΔt

$P_{f}$ = 1500(3.5 x $10^{4$ i - 1.8x $10^{4$ j) + (2736i + 3078j)(1.5x $10^{3$ )

$P_{f}$ =(5.7 x $10^{7$ i- 2.24 x $10^{7$ j)kgm/s

4 0

4 years ago

1. Which of the following is NOT a vector quantity? (a) Displacement. (b) Energy. (c) Force. (d) Momentum. (e) Velocity.

dem82 [27]

Answer:

B. energy

Explanation:

A vector has direction.

Energy does not have a direction.

5 0

3 years ago

Why is your weight the same any place on Earth?

Thepotemich [5.8K]

Answer: A person can weigh differently at various place on Earth because of the fluctuations in Earth's gravity, according to a new high-resolution map. ... Earth's gravity is weaker at the equator due to centrifugal forces produced by the planet's rotation

Explanation:

3 0

3 years ago

A grapefruit falls from a tree and hits the ground .75 seconds later. How far did the grapefruit drop? What was its speed?

Ivanshal [37]

1) The grapefruit is in free fall, so it moves by uniformly accelerated motion, with constant acceleration $g=9.81 m/s^2$ . Calling h its height at t=0, the height at time t is given by
$h(t)=h- \frac{1}{2}gt^2$
We are told thatn when $t=0.75 s$ the grapefruit hits the ground, so h(0.75 s)=0. If we substitute these data into the equation, we can find the initial height h of the grapefruit:
$0=h- \frac{1}{2}gt^2$
$h= \frac{1}{2}gt^2= \frac{1}{2}(9.81 m/s^2)(0.75 s)^2=2.76 m$

2) The speed of the grapefruit at time t is given by
$v(t)=v_0 +gt$
where $v_0=0$ is the initial speed of the grapefruit. Substituting t=0.75 s, we find the speed when the grapefruit hits the ground:
$v(0.75 s)=gt=(9.81 m/s^2)(0.75 s)=7.36 m/s$

3 0

4 years ago

what would someones mass be if their weight was 158.4? This is for science homework, they gave me a random weight # but no mass.

bekas [8.4K]

ON EARTH, every kilogram of mass weighs about 2.205 pounds.

So if you know the weight (in pounds), and you know that it was
weighed on Earth, you can simply divide the pounds by 2.205 ,
and you'll get the mass (in kilograms).

I can see that on this science homework, they used 2.2 for the weight
of 1 kilogram expressed in pounds. So just divide the weight by 2.2
to get the mass in kilograms.

(The weight number they gave you is not so random. :-) )

8 0

3 years ago