Answer:
a

b

Explanation:
From the question we are told that
The child's weight is 
The length of the sliding surface of the playground is 
The coefficient of friction is 
The angle is 
The initial speed is 
Generally the normal force acting on the child is mathematically represented as
=> 
Note 
Generally the frictional force between the slide and the child is

Generally the resultant force acting on the child due to her weight and the frictional force is mathematically represented as

Here F is the resultant force and it is represented as 
=> 
=> 
=> 
=>
So

=> 
Generally the heat energy generated by the frictional force which equivalent tot the workdone by the frictional force is mathematically represented as

=> 
=> 
Generally from kinematic equation we have that

=> 
=> 
=> 
Answer:
14 hours 18 minutes.
Explanation:
ratio of number of orbits, so it completes 7 orbits in the time Janus does 6.
(16*60+41)*6/7=858 minutes or 14 hours 18 minutes
Explanation:
its either a or d however i say the best choice is d
Answer: 
Explanation:
If we make an analysis of the net force
of the rock that was thrown upwards, we will have the following:
(1)
Where:
is the force with which the rock was thrown
is the weight of the rock
Being the weight the relation between the mass
of the rock and the acceleration due gravity
:
(2)
(3)
Substituting (3) in (1):
(4)
(5) This is the net Force on the rock
On the other hand, we know this force is equal to the multiplication of the mass with the acceleration, according to Newton's 2nd Law:
(6)
Finding the acceleration
:
(7)
(8)
Finally: