Answer:
955.5N
Explanation:
The normal force is given by the difference between the centripetal force and gravity at the top of the loop:

mass m = 65kg
radius of the loop r = 4m
velocity v = ?
g = 9.8 m/s²
To find the centripetal force, you need to find the velocity of the car at the top of the loop.
Use energy conservation:

At the top of the hill:

At the top of the loop:

Setting both energies equal and canceling the mass m gives:

Solving for v:

Using v in the first equation:

The ice and how the blades are made
Answer:
Tangential acceleration is in the direction of velocity - along the circumference of a circle if the object is undergoing circular motion
a = (V2 - V1) / T
Radial acceleration is perpendicular to the direction of motion if the object is not moving in a straight line (perhaps along the circumference of a circle)
a = m V^2 / R = m ω^2 R where R is the radius vector of the velocity - note that the Radius vector is directed from the center of motion to the object and for circular motion would be constant in magnitude but not in direction
1. Air resistance (therefore, the air density, shape (aerodynamic or not), and surface area affected
2. The gravitational acceleration constant (g = 9.8 m/s^2 on Earth)
<span>As the body rises up its gravitational potential energy increases but its kinetic energy decreases.
As a body falls its gravitational potential energy decreases but it's kinetic energy increases</span>