Answer:
a)r' = 4 r
b)
Explanation:
Given that car is moving with uniform speed.
At the verge of sliding
Friction force = Force due to circular motion

So we can say that
-----1
Where is the coefficient of friction
r is the radius of circular path
V is the velocity of car
a)
if the car speed become double
It means that new speed of car =2V
lets tale new radius of circular path is r'
---------2
From equation 12 and 2 we cay that
r' = 4 r
It means that we have to increase radius 4 times to avoid sliding
b)
In the above expression there is no any terms of mass ,it means that sliding speed does not depends on the weight of car.
So the sliding speed will remain same.
The wind you would use to travel from Spain west to Florida are The Trade Winds
Answer:

Explanation:
For answer this we will use the law of the conservation of the angular momentum.

so:

where
is the moment of inertia of the merry-go-round,
is the initial angular velocity of the merry-go-round,
is the moment of inertia of the merry-go-round and the child together and
is the final angular velocity.
First, we will find the moment of inertia of the merry-go-round using:
I = 
I = 
I = 359.375 kg*m^2
Where
is the mass and R is the radio of the merry-go-round
Second, we will change the initial angular velocity to rad/s as:
W = 0.520*2
rad/s
W = 3.2672 rad/s
Third, we will find the moment of inertia of both after the collision:



Finally we replace all the data:

Solving for
:

Electromagnets are used for various purposes but I fathom in this instance, the questioner is asking about how electromagnetics can be used to attraction or repulsion.
Example, electromagnets are used for attraction in cranes which attach them to containers in order to lift them.
Meanwhile, Maglev trains use electromagnets repulsive properties.