Answer:
Explanation:
Time of flight is the time taken by the bulet in air. Time of flight is expressed as T = Usinθ/g where;
U is the initial velocity = 180m/s
θ is the angle of launch = 90° (Since the bullet is shot upwards)
g is the acceleration due to gravity = 9.81m/s²
T = 180sin90/9.81
T = 180/9.81
T = 18.35s
<em>Hence the bullet will spend 18.35s in air</em>
<em></em>
The height covered by the bullet is the maximum height. Maximum height is expressed as;
H = u²sin²θ/2g
H = 180²sin²90/2(9.81)
H = 180/19.62
H = 9.17m
<em>Hence the bullet will go 9.17m high</em>
Answer:
wrong answer because m=100
Answer:
Option D.
A fan is turned from high speed to low speed.
Explanation:
It is important to note that air is also a fluid.
In a system, static pressure of air increases with the speed of rotation of the fan. This is because when the speed of the fan is increased, the force with which it is pushing the air molecules is increased. Since pressure is a relationship between force and area, the pressure of the air molecules will be increased.
Conversely, when the speed of the fan is reduced, the priming force on the air molecules will be reduced, hence the pressure of the air will drop.
This makes option D the correct option
Answer:
Explanation:
Resistivity and resistance are proportional and depends of the length and the cross-sectional area of the wire:
furthermore, the density is the mass divided by the volume, and the volume can be written as the area multiplyed by the length:
Now you have tw equations and two variables, so you can solve for each of them.
first, solve for A in both equations and replace them:
now replace this into any of the previous equiations:
If you assume the wire has circular cross-sectional area, then the area is:
solving for d:
replacing A and simplifying: