Friction- the external force that acts on objects and causes them to slow down when no other external force acts upon them.
Looks like you need to review through the lesson and take notes as it tells you in the lesson what each of these are.
Answer:
Wilhelm Conrad Roentgen (1845-1923)
Antoine Henri Becquerel (1852-1908)
Pierre (1859-1906) and Marie (1867-1934) Curie
Explanation:
Wilhelm Conrad Roentgen (1845-1923)
Contribution: Discovery of x-rays in 1901.
Antoine Henri Becquerel (1852-1908)
Contribution: He discovered that radioactivity is the separation of x-rays and document and the difference between two.
Pierre (1859-1906) and Marie (1867-1934) Curie
Contribution: She discovered Polonium and Radium in1911
Answer:
Explanation:
Given:
height above which the rock is thrown up,
initial velocity of projection,
let the gravity on the other planet be g'
The time taken by the rock to reach the top height on the exoplanet:
where:
final velocity at the top height = 0
(-ve sign to indicate that acceleration acts opposite to the velocity)
The time taken by the rock to reach the top height on the earth:
Height reached by the rock above the point of throwing on the exoplanet:
where:
final velocity at the top height = 0
Height reached by the rock above the point of throwing on the earth:
The time taken by the rock to fall from the highest point to the ground on the exoplanet:
(during falling it falls below the cliff)
here:
initial velocity= 0
Similarly on earth:
Now the required time difference: