C)Electric Charges Produce Electric Fields
Answer:
6.65m/s
Explanation:
Using the equation of motion
S = ut + 1/2gt²
S is the height of fall
t is the time
u is the horizontal velocity
g is the acceleration due to gravity
Given
S = 300 + 50
S = 350m
t = 7.8seconds
g = 9.8m/s^2
Get S
S = 7.8u + 1/2(9.8)(7.8)²
S = 7.8u + 298.116
350 = 7.8u + 298.116
7.8u = 350 - 298.116
7.8u = 51.884
u = 51.884/7.8
u = 6.65m/s
Hence the rock's horizontal velocity was 6.65m/s
Answer:
2. The metal surface exerts less frictional force because there are fewer bumps and irregularities on it than there are on the concrete.
Explanation:
Frictional force is a force that is exerted between two surfaces in contact with each other. Frictional force always opposes the direction of relative motion of the two surfaces: for instance, for a ball moving along a surface, the force of friction exerted by the surface on the ball points opposite to the direction of motion of the ball.
The magnitude of the frictional force for a ball moving on a flat surface is given by

where
is the coefficient of friction
m is the mass of the ball
g is the acceleration of gravity
The value of
depends on the type of surface involved. In particular, a smooth surface has a smaller value of
, while a rough surface will have a bigger value. In this case, we are comparing a smooth metal surface with concrete: since the metal surface has fewer bumps and irregularities than concrete, it has a smaller value of coefficient of friction, so it exerts less frictional force than concrete.
Aerodynamic is relating to reduces the drag from air moving past
Answer:
0.1667Hz
Explanation:
by explanation frequency is given by 1/time
after carrying out the calculation of time we can easily get frequency.
time=speed/distance
=18/3
=6s
but frequency=1/time
hence=1/6
=0.1667hertz