Bubbles came off from the copper pennies are hydrogen gas. There many free hydrogen ions in an acid like vinegar. And because of the chemical reaction between the copper and the vinegar, many hydrogen ions joined together to form hydrogen gas.
Answer:
The answer is C
Explanation:
The magnitude of the gravitational force depends inversely on the square of the radial distance between the centers of the two masses. Thus, essentially, the force can only fall to zero, when the denominator that is r becomes infinite.
The density will be 1.05
The mass will be 13.65
Answer:
speed of plane in still air = 1060 km/h
speed of wind = 170 km/h
Explanation:
Let teh speed of plane in still air is vp and the speed of air is va.
Irt travels 2670 km in 3 hours against the wind
So,
vp - va = 2670 / 3 = 890 km/h ..... (1)
It travels 11070 km in 9 hours along the wind.
vp + va = 11070 / 9 = 1230 km/h .... (2)
Adding both the equations
2 vp = 2120
vp = 1060 km/h
and va = 1230 - vp = 1230 - 1060 = 170 km/h