Answer:
1.) Time t = 3.1 seconds
2.) Height h = 46 metres
Explanation:
given that the initial velocity U = 30 m/s
At the top of the trajectory, the final velocity V = 0
Using first equation of motion
V = U - gt
g is negative 9.81m/^2 as the object is going against the gravity.
Substitute all the parameters into the formula
0 = 30 - 9.81t
9.81t = 30
Make t the subject of formula
t = 30/9.81
t = 3.058 seconds
t = 3.1 seconds approximately
Therefore, it will take 3.1 seconds to reach to reach the top of its trajectory.
2.) The height it will go can be calculated by using second equation of motion
h = ut - 1/2gt^2
Substitutes U, g and t into the formula
h = 30(3.1) - 1/2 × 9.8 × 3.1^2
h = 93 - 47.089
h = 45.911 m
It will go 46 metres approximately high.
Answer:Train A is 90 m long and running at 72 km/h.
Train B is 120 m long and running at 36 km/h.
When the trains are running in opposite directions, their relative speed gets added: 72+36 = 108 km/h.
The total length of A and B = 90+120 = 210 m
So the time taken to cross each other = 210 m*60*60/108*1000m
= 7 seconds
Explanation:
Explanation:
In Europe the standard voltage in homes is 220 V instead of the 120 V used in the United States.
100-W European bulb would be intended for use with a 220-V potential difference.
(a) If V = 220 V and P = 100 W
Power :
If you bring a "100-W" European bulb home to the untied States, what should be its US power rating. So,
or
P = 29.8 watts
(b) Let I is the current will the 100-W European bulb draw in normal use in the United States. So,
Hence, this is the required solution.
It depends on the tempature of something or an object,
The Object has to go from hot to cold, that is a primary example of how heat transfer occurs
Answer:
Explanation:
Optical telescopes collect visible light. The three main types are reflecting telescopes, refracting telescopes, and catadioptric telescopes. Radio telescopes collect and focus radio waves from distant objects. Space telescopes orbit Earth, collecting wavelengths of light that are normally blocked by the atmosphere.
