Answer:
Explanation:
Given data
Flight distance S=4890 km
Time difference Δt=t₂-t₁=40 min
Air speed of plane=980 km/h
To find
Speed of jet stream
Solution
When moving in the same direction as the jet stream time taken as t₁=d/(v+vs),v is velocity of plane and vs is velocity of plane
While moving in opposite direction t₂=d/(v+vs)
So
Apply quadratic formula to solve for vs
So
Answer:
Explanation:
Conservation of momentum
Initial momentum is zero as both gun and bullet are motionless in the frame of reference before firing.
0 = 0.012(1500.0) + 4.0v
v = - 4.5 m/s
Must be a rail gun as the fastest powder driven bullets are moving at roughly half the speed described.
Answer:
11.18 minutes
Explanation:
We shall apply Newton's law of cooling
Rate of cooling ∝ Temperature difference
(T₂ - T₁ ) / t = k ( T₁ + T₂ / 2 - T )
A body cools from temperature of T₂ TO T₁ in time t , K being a constant.
(T₁ + T₂) /2 is the average temperature and T is temperature of surrounding.
Using the data given in the problem ,
For cooling from 425 degree to 300 degree
For cooling from 425 to 135 in time t we have
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= 209k
From these two equations we get the value of t as
t = 16.18 s
So time required to cool from 300 to 135 degree isas follows
16.18 - 5 = 11.18 s
Answer: one of the answers should be increase the number of turns of wire on the nail
Explanation: the more you wrap the Wire on a nail, its electromagnet would increase