Just wondering if I did this right

A piece of warm concrete is placed in a cold-water tank, and energy flows between the concrete and the water. Which way does the

sammy [17]

Answer:

Heat flows from hot to cold objects. When a hot and a cold body are in thermal contact, they exchange heat energy until they reach thermal equilibrium, with the hot body cooling down and the cold body warming up. This is a natural phenomenon we experience all the time.

Explanation:

3 0

2 years ago

Using the right amount of significant figures, calculate the answer to the following problem, 215.5+101.02555

cestrela7 [59]

Answer:

This is how I figured it out:

215.5 rounded to one significant figure is 200
101.02555 rounded to one significant figure is 100.
200 + 100 = 300.

Hope this helps!

Explanation:

7 0

3 years ago

A 150 kg boy and his bike are traveling 12 m/s when he slams on his breaks and stop at his friend’s house. How much impulse is r

Nataly [62]

Answer:

J = 1800 kg-m/s

Explanation:

Given that,

Mass of a boy, m = 150 kg

Initial velocity of a boy, u = 12 m/s

Finally, it stops, v = 0

We need to find the impulse is required to produce this change in momentum. We know that impulse is equal to the change in momentum. So,

$J=m(v-u)\\\\=150\times (0-12)\\\\=-1800\ kg-m/s\\\\|J|=1800\ kg-m/s$

So, the impulse is equal to 1800 kg-m/s

4 0

3 years ago

(III) A baseball is seen to pass upward by a window with a vertical speed of If the ball was thrown by a person 18 m below on th

Ghella [55]

Answer:

Assuming that the vertical speed of the ball is 14 m/s we found the given values:

a) V₀ = 23.4 m/s

b) h = 27.9 m

c) t = 0.96 s

d) t = 4.8 s

Explanation:

a) Assuming that the vertical speed is 14 m/s (founded in the book) the initial speed of the ball can be calculated as follows:

$V_{f}^{2} = V_{0}^{2} - 2gh$

Where:

$V_{f}$ : is the final speed = 14 m/s

$V_{0}$ : is the initial speed =?

g: is the gravity = 9.81 m/s²

h: is the height = 18 m

$V_{0} = \sqrt{V_{f}^{2} + 2gh} = \sqrt{(14 m/s)^{2} + 2*9.81 m/s^{2}*18 m} = 23.4 m/s$

b) The maximum height is:

$V_{f}^{2} = V_{0}^{2} - 2gh$

$h = \frac{V_{0}^{2}}{2g} = \frac{(23. 4 m/s)^{2}}{2*9.81 m/s^{2}} = 27.9 m$

c) The time can be found using the following equation:

$V_{f} = V_{0} - gt$

$t = \frac{V_{0} - V_{f}}{g} = \frac{23.4 m/s - 14 m/s}{9.81 m/s^{2}} = 0.96 s$

d) The flight time is given by:

$t_{v} = \frac{2V_{0}}{g} = \frac{2*23.4 m/s}{9.81 m/s^{2}} = 4.8 s$

I hope it helps you!

3 0

3 years ago

Whqt do you mean by geo-stationery satellite? Explain.

Ratling [72]

Answer:

Description: When a geosynchronous satellite is placed directly above the Equator with a circular orbit and angular velocity identical to that of the Earth, the satellite is known as a geostationary satellite

Explanation:

These satellites appear to be stationary above a particular point which is due to the synchronization. This type of satellite provides a distinct benefit of fixing the receiving antennas at one place, hence making them more economical than regular tracking antennas. Over the years, these satellites have helped in revolutionizing the global communications, weather forecasting and television broadcasting. When the orbit of a geosynchronous satellite is not aligned directly over the equator, the orbit is known as an inclined orbit.

8 0

3 years ago