Answer:
The answer to the first one is, group 1.
Explanation:
Sorry if this didn’t help if I find the answers to the others I’ll comment them to myself!
Answer:
<em>The crane lifts the crate up to 76 m high</em>
Explanation:
<u>Work Done by a Force</u>
The work done by a force of magnitude F that displaces an object by a distance y is given by

We know a crane does a work of 9,500 Joule to lift a crate and is using a force of 125 Nw.
The above equation can be solved to know the value of y in terms of the work and the force:

Plugging in the given values


The crane lifts the crate up to 76 m high
Answer:
speed of each marble after collision will be 1.728 m/sec
Explanation:
We have given mass of the marble 
Velocity of marble 
Its collides with other marble of mass 25 gram
So mass of other marble 
Second marble is at so 
We have to find the velocity of second marble
From momentum conservation we know that
, here v is common velocity of both marble after collision
So 
v = 1.428 m /sec
So speed of each marble after collision will be 1.728 m/sec
You can find the mass of an atom by adding the number of protons and neutrons. In this case the atom has 2 protons and 3 neutrons so the mass is 5.
Answer:
Check the explanation
Explanation:
The escape velocity is the velocity needed by any object to overcome the gravitational force of the planet on which it’s present. Now we know that the gravitational force is directly proportional to the mass of the planet and inversely proportional to the distance of the object from the center of planet.
If we keep the mass of earth constant and decrease the size of the earth than this will decrease the distance between the object and the center of the earth and thus the gravitational force that will act on the body will increase substantially which will in turn increase the value of the escape velocity.
The value of escape velocity will keep on increasing as the size of the earth will shrink till it reaches to a point when the value of escape velocity becomes more than the speed of light and since it’s impossible to travel with a speed greater than the speed of light and therefore at this point it will become impossible for a spacecraft to escape the earth.