Answer:
18.9 m.
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Final velocity (v) = 70 km/h
Height (h) =?
Next, we shall convert 70 km/h to m/s. This can be obtained as follow:
3.6 km/h = 1 m/s
Therefore,
70 km/h = 70 km/h × 1 m/s / 3.6 km/h
70 km/h = 19.44 m/s
Finally, we shall determine the height. This can be obtained as follow:
Initial velocity (u) = 0 m/s
Final velocity (v) = 19.44 m/s
Acceleration due to gravity (g) = 10 m/s²
Height (h) =?
v² = u² + 2gh
19.44² = 0² + (2 × 10 × h)
377.9136 = 0 + 20h
377.9136 = 20h
Divide both side by 20
h = 377.9136 / 20
h = 18.9 m
Thus, the car will fall from a height of 18.9 m
Answer: True
Explanation:
A photo detector that can respond to the entire rang of visible light can be design, it is true.
Photo detector is a device in an optical receiver which receives optical signals and convert it to electric signal. It is the key device position in front of the optical receiver.
Answer:
a) , b)
Explanation:
a) The Hooke's law states that spring force is directly proportional to change in length. That is to say:
In this case, the force is equal to the weight of the object:
The spring constant is:
b) The length of the spring is:
Answer:
P = 4.5 watts
Explanation:
Given that,
EMF of the circuit, E = 3 volt
The resistance of the resistors, R = 2 ohms
We need to find the power of this circuit. The relation between power, emf and resistance is given by the formula as follows :
Substitute all the values,
So, the power of this circuit is equal to 4.5 watts.
Explanation:
If you cannot visualize it, just assume that the distance from station A to B is 420km. Each half is 210km.
When the car travels from A to B, it takes 420/30 = 14 hours.
When the car travels from B to the halfway point, it takes 210/30 = 7 hours.
When the car travels from the halfway point to A, it takes 210/70 = 3 hours.
Total time taken = 14 + 7 + 3 = 24 hours.
Total distance = 420km * 2 = 840km.
Hence, the average speed of the car is 840/24 = 35km/h.