Answer:
v = 12.12 m/s
Explanation:
Given that,
The mass of the cart, m = 75 kg
The roller coaster begins 15 m above the ground.
We need to find the velocity of the cart halfway to the ground. Let the velocity be v. Using the conservation of energy at this position, h = 15/2 = 7.5 m
So, the velocity of the cart is 12.12 m/s.
The gravitational force acting on the man is 800 N towards the Earth's centre
Explanation:
The weight of an object on the Earth is exactly the gravitational force exerted by the Earth on the object.
The gravitational force exerted by the Earth on an object located at the Earth's surface is given by:
where
G is the gravitational constant
M is the Earth's mass
m is the mass of the object
R is the radius of the Earth
And the direction of the force is towards the Earth's centre.
Since G, M and R are constant, they are grouped into a single constant called g, acceleration of gravity:
therefore the gravitational force can be rewritten as
And this is the usual equation that we use to calculate the weight of an object.
Therefore, weight and gravitational force acting on an object on Earth are the same thing: so, the gravitational force acting on the man is equal to his weight, 800 N, and it acts towards the Earth's center.
Learn more about weight and gravitational force:
#LearnwithBrainly