Answer:
a) 0 metres
b) From time 0 s to 10 s , the car was accelerated. Its velocity accelerated from 0m/s to 20 m/s
c) 20 m/s
Explanation:
a) <em>Formula of displacement= velocity x time</em>
time=40 s
velocity =0 m/s
∴ displacement= 0 x 40 = 0 m
Magnitude of displacement is 0 m
b) The increase in velocity shows that there has been acceleration.
c) The average velocity of the car is =
{initial velocity + final velocity}
=
=20
Therefore, the magnitude of the average velocity of the car is 20 m/s
To solve this problem we will apply the linear motion kinematic equations. We will find the two components of velocity and finally by geometric and vector relations we will find both the angle and the magnitude of the vector. In the case of horizontal speed we have to



The vertical component of velocity is

Here,
h = Height
g = Gravitational acceleration
t = Time
= Vertical component of velocity



The direction of the velocity will be given by the tangent of the components, then



The magnitude is given vectorially as,



Therefore the angle is 55.59° and the velocity is 26.37m/s
Answer:
1. 0.574 kJ/kg
2. 315.7 MW
Explanation:
1. The mechanical energy per unit mass of the river is given by:


Where:
Ek is the kinetic energy
Ep is the potential energy
v is the speed of the river = 3 m/s
g is the gravity = 9.81 m/s²
h is the height = 58 m

Hence, the total mechanical energy of the river is 0.574 kJ/kg.
2. The power generation potential on the river is:

Therefore, the power generation potential of the entire river is 315.7 MW.
I hope it helps you!
Hello! I can help you with this!
4. For this problem, we have to write and solve a proportion. We would set this proportion up as 12/15 = 8/x. This is because we're looking for the length of the shadow and we know the height of the items, so we line them up horizontally and x goes with 8, because we're looking for the shadow length. Let's cross multiply the values. 15 * 8 = 120. 12 * x = 12. You get 120 = 12x. Now, we must divide each side by 12 to isolate the "x". 120/12 is 10. x = 10. There. The cardboard box casts a shadow that is 10 ft long.
5. For this question, you do the same thing. This time, you're finding the height of the tower, so you would do 1.2/0.6 = x/7. Cross multiply the values in order to get 8.4 = 0.6x. Now, divide each side by 0.6x to isolate the "x". 8.4/0.6 is 14. x = 14. There. The tower is 14 m tall.
If you need more help on proportions and using proportions in real life situations, feel free to search on the internet to find more information about how you solve them.