Answer:
The astronaut's weight will be one-forth of her normal weight on earth.
Explanation:
From Newton's law of gravitation, we can write the acceleration due to gravity (g) on Earth's surface is given by
where 'G' is gravitational constant, '
' is Earth's mass and 'R' is Earth's radius.
As shown in the figure, if the astronaut is at a height 'h' from earth's surface and if '
' be the value of the acceleration due to gravity at that height, then
Taking the ratio of both the equations, and as given h = R.
So,
where 'm' is the mass of the astronaut.
So the weight of the astronaut will be one-forth her normal weight on earth.
Answer:
Explanation:
As we stir the pot of soup by a metal spoon which is a conductor, it conducts the heat and starts heating after some time the temperature of the spoon rises and we are not able to hold the spoon and we get burns.
The amount of work done can be solved using the formula:
Work = Force x Distance = Change in kinetic energy
Kinetic energy can be solved using the formula: KE = (1/2)*m*v^2
So, change in kinetic energy = (1/2)*m*(Vf)^2 - (1/2)*m*(Vo)^2
Where:
Vf = final velocity = 90 kph = 25 m/s
Vo = initial velocity = 72 kph = 20 m/s
substituting the given values:
Work = (1/2)*2500*(25^2) - (1/2)*2500*(20^2) = 281250 J, which can also be expressed as 2.8 x 10^5 Joules.
Among the choices, the correct answer is A.
P = m * v
v = {3i - 4j} = square root (3^2 + 4^2) = 5
P = 20 * 5
P = 100 kg m/s
