Answer:
70 revolutions
Explanation:
We can start by the time it takes for the driver to come from 22.8m/s to full rest:
The tire angular velocity before stopping is:
Also its angular decceleration:
Using the following equation motion we can findout the angle it makes during the deceleration:
where 
= 0 m/s is the final angular velocity of the car when it stops, 
= 114rad/s is the initial angular velocity of the car 
= 14.75 rad/s2 is the deceleration of the can, and 
is the angular distance traveled, which we care looking for:
or 440/2π = 70 revelutions
Basically, when someone is resting in an accelerated vehicle without restraint from a seatbelt, the force of stopping the vehicle will be when inertia occurs, and that force of the vehicle coming to a stop will affect the passenger (without a seatbelt/restraint from another force or object) greatly by throwing them.
For example;
If I were to be riding in a vehicle (without a seatbelt) that's accelerating at 40 m/s^2 and it suddenly gets slammed on the breaks, I will be thrown forward from inside the vehicle.
I hope this helps!
Answer:
Force = 35 N
Explanation:
From Newton's third law of motion, the boy must apply a force greater than the weight of the sled to lift it.
weight of sled = mg
where m is its mass and g the force of gravity on it.
weight of sled = 50 N
Force applied by the boy on the sled = 15 N
Since the force applied on the sled by the boy is lesser than the weight of the sled, then;
Force that the sled exerts on the student = 50 - 15
= 35 N
The force exerted by the sled on the student is 35 N.
