Answer:
1331.84 m/s
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity = 0
s = Displacement = 490 km
a = Acceleration
g = Acceleration due to gravity = 1.81 m/s² = a
From equation of linear motion

The speed of the material must be 1331.84 m/s in order to reach the height of 490 km
Answer:
the inductive reactance of the coil is 1335.35 Ω
Explanation:
Given;
inductance of the coil, L = 250 mH = 0.25 H
effective current through the coil, I = 5 mA
frequency of the coil, f = 850 Hz
The inductive reactance of the coil is calculated as;

Therefore, the inductive reactance of the coil is 1335.35 Ω
Answer:
6 s
Explanation:
given,
Sports car accelerate from 0 to 30 mph in 1.5 s
time taken to accelerate 0 to 60 mph = ?
The power of the engine is independent of velocity and neglecting friction
power =
P = constant
the kinetic energy for 60 mph larger than this of 30 mph
= 
= 
= 
= 4
gain in kinetic energy = P x t
time = 4 x 1.5
= 6 s
Archaeological evidence shows that Egyptians worked together to build the pyramids. Remains of quarries and ancient tools suggest that large slabs were created from rock beds. The slabs were placed on sleds and pulled to the building site. To make this process easier, men most likely poured oil on the roadway. This process is depicted in tomb paintings that date back to 1900 BCE.
Answer:
0.12 K
Explanation:
height, h = 51 m
let the mass of water is m.
Specific heat of water, c = 4190 J/kg K
According to the transformation of energy
Potential energy of water = thermal energy of water
m x g x h = m x c x ΔT
Where, ΔT is the rise in temperature
g x h = c x ΔT
9.8 x 51 = 4190 x ΔT
ΔT = 0.12 K
Thus, the rise in temperature is 0.12 K.