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3 years ago

Object is dropped from the top of a building that is 1125 m tall at the point when it’s speed is 30 m/s how far has it fallen

Physics

1 answer:

FrozenT [24]3 years ago

4 0

-- Gravity makes a falling object fall 9.8 m/s faster every second.

-- So, it reaches the speed of 30 m/s in (30/9.8) = 3.06 seconds after it's dropped.

-- The distance an object falls from rest is D = 1/2 (acceleration) (time)²

D = 1/2 (9.8 m/s²) (3.06 sec)²

D = (4.9 m/s²) (9.37 sec²)

<em>D = 45.8 meters</em>

Notice that we don't care how high the building is. The problem works just as long as the object can reach 30 m/s before it hits the ground. That turns out to be anything higher than 45.8 meters for the drop . . . maybe something like 13 floors or more.

Now I'll go a little farther for you ! Writing the last paragraph made me a little curious and uncomfortable. So I went and looked up the world's tallest buildings . . . and I found out that this problem could never happen !

The tallest building in the world now is the Burj Khalifa, in Dubai. It has 163 floors, and it's 828 meters high ! That's 2,717 feet. It's gonna be a long time before there's a building that's 1125 meters tall, like this problem says. That's close to 3700 feet . . . I've had flying lessons where I wasn't that far off the ground !

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The kicker now kicks the ball with the same speed as in the number of 4,but at 60.0°from the horizontal or 30.0° from the vertic

Shkiper50 [21]

Answer:

i) 0.7

ii) 1.39

iii) 0.6

Next time, when compiling a Physics question, ensure you put the unit of each measurement.

Explanation:

i) T = time of flight = $\frac{2uSin(A)}{g}$

where u = speed = 4, A = 60 and g = acceleration due to gravity = 10 (It is a constant);

Subsituting the values, we have: T = $\frac{2(4)Sin(60)}{10}$ = 0.7

ii) distance travel = Range = R = $\frac{u^{2}Sin(2A) }{g}$

where u = speed = 4, A = 60 and g = acceleration due to gravity = 10 (It is a constant);

Subsituting values, we have: R = $\frac{4^{2}Sin(2*60) }{10}$ = 1.39

iii) Maximum Height = H = $\frac{u^{2}(Sin(A))^{2} }{2g}$

where u = speed = 4, A = 60 and g = acceleration due to gravity = 10 (It is a constant);

Subsituting values, we have: $\frac{4^{2}(Sin60)^{2} }{2*10}$ = 0.6

4 0

3 years ago

A bowling ball is dropped from rest. what is the ball’s velocity after falling for 4 seconds?

muminat

Answer:

it would be 39.2 m/s

Explanation:

After one second, you're falling 9.8 m/s. After two seconds, you're falling 19.6 m/s, and so on.

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3 years ago

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It is true
I hope this helps

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3 years ago

A 150 g baseball is traveling horizontally at 50 m/s. If the ball takes 20 ms to stop once it is in contact with the catcher’s g

Sliva [168]

To solve for force, you need to get the product of mass and acceleration.
F = ma

Your given is:
m = 150g
a = ?
v = 50 m/s
t = 20ms

As you can see, you do not have acceleration yet. But if you read the problem you can come up with the formula of acceleration.
Acceleration is the change in velocity over a period of time.

a = change in velocity/time

To get the change in velocity, you get the difference between the initial velocity and final velocity:

$a = \frac{vf-vi}{t}$

The ball was moving initially at a velocity of 50 m/s and it came to a stop. This is your clue. If a ball comes to a stop then that means that the final velocity of the ball is 0 m/s.

So we can put it into our formula now:

$a = \frac{0m/s-50m/s}{20ms}$

WAIT! As you can see, the units do not match. We have ms and s into our equation and that means you cannot proceed till they are the same. First we need to convert ms to s.

$20ms$ x $\frac{1s}{1000ms}$ = $\frac{20s}{1000} = 0.02s$

So your new time is 0.02s. Now we put this time into the formula:

$a = \frac{0m/s-50m/s}{0.02s}$
$a = \frac{-50m/s}{0.02s} = -2,500 m/ s^{2}$

As you can see our acceleration is a negative value, this indicates that it decelerated or slowed down which makes sense because it was brought to a stop.

So now we have our acceleration. Now using this, we can get our force.

$F= ma$

Before we start doing this, you need to take note that the unit of force is N, but when you expand it, it is $kg.m/ s^{2}$ but as you can see our mass given is in grams. So again, before you put them into the equation we need to change it into kg first.

$150g = \frac{1kg}{1,000g} = \frac{150kg}{1,000} = 0.150kg$

Our new mass is 0.150kg.

To make things clearer, let us write down all our new values:

m = 0.150kg
a = -2,500 $m/ s^{2}$

Now that all our units match, we can put that into our formula:

$F= ma$
$F= (0.150kg)(-2,500m/s^{2})$
$F = -375kg.m/ s^{2} or -375N$

The value again is negative because it is going against the initial direction of the ball. But if your instructor just wants to get the value of force or the magnitude of the force, just disregard the sign.

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3 years ago

Which of the following is an example of balanced forces?

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A seesaw remains stationary when two students of equal weight sit on the ends

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