Ask question

Ask question

All categories

2 years ago

15

A 2.6 kg rock is dropped from a height of 10 m. With what speed will it strike the ground. Ignore air resistance. Solve using co

nservation of energy (start with Ebefore = Eafter).

1 answer:

timurjin [86]2 years ago

5 0

Answer:

$mgh = \frac{1}{2} m {v}^{2} \\ v = \sqrt{2gh} \\ = \sqrt{2 \times 9.8 \times 10} \: m. {s}^{ - 1}$

You might be interested in

A jet is travelling at a speed of 1200 km/h and drops cargo from a height of 2.5 km above the ground Calculate the time it takes

OLEGan [10]

a) Time of flight: 22.6 s

To calculate the time it takes for the cargo to reach the ground, we just consider the vertical motion of the cargo.

The vertical position at time t is given by

$y(t) = h +u_y t - \frac{1}{2}gt^2$

where

h = 2.5 km = 2500 m is the initial height

$u_y = 0$ is the initial vertical velocity of the cargo

g = 9.8 m/s^2 is the acceleration of gravity

The cargo reaches the ground when

$y(t) = 0$

So substituting it into the equation and solving for t, we find the time of flight of the cargo:

$0 = h - \frac{1}{2}gt^2\\t=\sqrt{\frac{2h}{g}}=\sqrt{\frac{2(2500)}{9.8}}=22.6 s$

b) 7.5 km

The range travelled by the cargo can be calculated by considering its horizontal motion only. In fact, the horizontal motion is a uniform motion, with constant velocity equal to the initial velocity of the jet:

$v_x = 1200 km/h \cdot \frac{1000 m/km}{3600 s/h}=333.3 m/s$

So the horizontal distance travelled is

$d=v_x t$

And if we substitute the time of flight,

t = 22.6 s

We find the range of the cargo:

$d=(333.3)(22.6)=7533 m = 7.5 km$

7 0

2 years ago

Which of the following statements describes an anticyclone?

marshall27 [118]

The answer is B high pressure.

3 0

2 years ago

How come in free fall you feel weightless even though gravity is pulling down on you?

AysviL [449]

Feeling of Weight.

When walking, you feel the weight on your feet, therefore, your brain automatically refers to it as a source of weight.

In the air there is no platform to land on, therefore the brain does not have the conscience to register you getting pulled down.

7 0

2 years ago

Help with this I can’t come up with anything

TEA [102]

Answer:

His third law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal and opposite force on object A. ... In reaction, a thrusting force is produced in the opposite direction.

Explanation:

8 0

2 years ago

45.678 g to 4 digits

PolarNik [594]

Answer:

<h2>45.68 g</h2>

Explanation:

Given 45.678 g, converting the value to 4 digits is similar to converting the decimal number to 4 significant figure. We can see that the decimal number initially contains 5 numbers. To covert to a 4 digits number we will convert the last digit which is 8 to 0 because 0 is insignificant.

If the number we are converting to zero is more than 4 then the preceding number (7) will be rounded up by adding 1 to it

The decimal number will become 45.68.

Note that the value of 7 was rounded up to 8 since the value we are converting to zero is more than 4.

<em>Hence the decimal value in 4 digits is 45.68 g</em>

7 0

2 years ago