C) because a new substance is formed
B) not sure but might be because the chemical properties of the substance has changed
Answer:
The take-off speed is 41.48 
Explanation:
Given :
Range
m
Projectile angle
13°
From the formula of range,

Find the velocity from above equation,

( ∵
)

Therefore, the take-off speed is 41.48
Answer:
(a) Current is 2831.93 A
(b) 
(c) 
Explanation:
Length of wire l = 3.22 m
Diameter of wire d = 7.32 mm = 0.00732 m
Cross sectional area of wire

Resistance 
Potential difference V = 33.7 volt
(A) current is equal to

(B) Current density is equal to


(c) Resistance is equal to



Solar roller is a cool name
The block moves with constant velocity: for Newton's second law, this means that the resultant of the forces acting on the block is zero, because the acceleration is zero.
We are only concerned about the horizontal direction, and there are only two forces acting along this direction: the force F pushing the block and the frictional force

acting against the motion. Since their resultant must be zero, we have:

The frictional force is

where

is the coefficient of kinetic friction

is the weight of the block.
Substituting these values, we find the magnitude of the force F: