That is because there are other forces like the friction forces that apply differently on both of them. The frictional forces applied to the sled are smaller than they are on the father, for example, so it's possible for him to pull it.
Answer:
15.88m/s
Explanation:
At the top of the roller coaster you will have three forces acting on the roller-coaster. See the image below. Fc is the centripetal force (for an object in circular motion), Fg is the gravitational force, and Fn is the normal force. To achieve the minimum speed we assume the roller-coaster is barely touching the vertical loop and so the normal force is zero. This leaves two acting forces.

Answer: 329.28 m/s
Explanation:
Given that:
Distance of sound = 823.2 m
Time taken for sound = 2.5 seconds
The speed of traveling sound = ?
Speed is obtained by dividing the distance travelled by the time taken for the travel.
Speed = Distance / time
Speed = 823.2m/2.5 seconds
Speed = 329.28 m/s
Thus, the sound traveling as fast as 329.28 m/s
You are correct. It is D. Don't make me copy it.
Answer:
V = 42187 m/s = 42.18 km/s
Explanation:
given data:
mass of sun is 
radius of earth orbit is 
minimum speed can be determined by using following formula
}
where G is 
Plugging all value to get desired value

V = 42187 m/s = 42.18 km/s