Answer: The person will still have a mass of 90kg on Mars
Explanation: The Truth is, the mass of a body remains constant from place to place. It is the weight which is equal to {mass of body * acceleration due to gravity{g}} that varies from place to place since it is dependent on {g}.
In this case the person will have a Weight of 90*9.8 = 882N on Earth.
{ "g" on Earth is 9.8m/s²}
And a Weight of 90*3.3 = 297N on Mars.
{ From the question "g" on Mars is {9.8m/s²}/3 which is 3.3m/s²}
From this analysis you notice that the WEIGHT of the person Varies but the MASS remained Constant at 90kg.
Answer:
Option C
Explanation:
v= u + at
20 = 5 + a(5)
15= a(5)
a= 3 m/s²
Force = mass × acceleration
= 10 × 3
= 30 N
Newton's second law states that the product between the mass and the acceleration of an object is equal to the force applied:

from which we find an expression for the acceleration:

(1)
Both objects are moving by uniformly accelerated motion (because the force applied is constant), so we can also using the following relationship

(2)
where

is the final speed of the object

is the initial speed
S is the distance covered
By substituting (1) into (2), and by removing

(since the final velocity of the two objects is zero), we find


where we can ignore the negative sign (because the force F will bring another negative sign).
For the first object, we have
![S= \frac{(2.0 m/s)^2 (4.0 kg)}{2F} = \frac{8}{F} [m]](https://tex.z-dn.net/?f=S%3D%20%5Cfrac%7B%282.0%20m%2Fs%29%5E2%20%284.0%20kg%29%7D%7B2F%7D%20%3D%20%20%5Cfrac%7B8%7D%7BF%7D%20%5Bm%5D%20)
And for the second object we have
![S= \frac{(4.0 m/s)^2 (1.0 kg)}{2F} = \frac{8}{F} [m]](https://tex.z-dn.net/?f=S%3D%20%5Cfrac%7B%284.0%20m%2Fs%29%5E2%20%281.0%20kg%29%7D%7B2F%7D%20%3D%20%5Cfrac%7B8%7D%7BF%7D%20%5Bm%5D%20)
And since the braking force applied to the two objects is the same, the two objects cover the same distance.
Density = (mass) / (volume)
4,000 kg/m³ = (mass) / (0.09 m³)
Multiply each side
by 0.09 m³ : (4,000 kg/m³) x (0.09 m³) = mass
mass = 360 kg .
Force of gravity = (mass) x (acceleration of gravity)
= (360 kg) x (9.8 m/s²)
= (360 x 9.8) kg-m/s²
= 3,528 newtons .
That's the force of gravity on this block, and it doesn't matter
what else is around it. It could be in a box on the shelf or at
the bottom of a swimming pool . . . it's weight is 3,528 newtons
(about 793.7 pounds).
Now, it won't seem that heavy when it's in the water, because
there's another force acting on it in the upward direction, against
gravity. That's the buoyant force due to the displaced water.
The block is displacing 0.09 m³ of water. Water has 1,000 kg of
mass in a m³, so the block displaces 90 kg of water. The weight
of that water is (90) x (9.8) = 882 newtons (about 198.4 pounds),
and that force tries to hold the block up, against gravity.
So while it's in the water, the block seems to weigh
(3,528 - 882) = 2,646 newtons (about 595.2 pounds) .
But again ... it's not correct to call that the "force of gravity acting
on the block in water". The force of gravity doesn't change, but
there's another force, working against gravity, in the water.