False because opposites attract. :)
Answer: Skilled manpower is essential to carry out several development activities.
Explanation:
It's a multiple of 5 because you can't multiply anything by 2 and get 25
The question is incomplete, the complete question is;
A body initially at a all 100 degree centigarde cools to 60 degree centigarde in 5 minutes and to 40 degree centigarde in 10 minutes . What is the temperature of surrounding? What will be the temperature in 15 minutes?
Answer:
See explanation
Explanation:
From Newton's law of cooling;
θ1 - θ2/t = K(θ1 + θ2/2 - θo]
Where;
θ1 and θ2 are initial and final temperatures
θo is the temperature of the surroundings
K is the constant
t is the time taken
Hence;
100 - 60/5 = K(100 + 60/2 - θo)
100 - 40/10 = K(100 + 40/2 - θo)
8= (80 - θo)K -----(1)
6= (70 - θo)K -----(2)
Diving (1) by (2)
8/6 = (80 - θo)/(70 - θo)
8(70 - θo) = 6(80 - θo)
560 - 8θo = 480 - θo
560 - 480 = -θo + 8θo
80 = 7θo
θo = 11.4°
Again from Newton's law of cooling;
θ = θo + Ce^-kt
Where;
t= 0, θ = 60° and θo = 11.4°
60 = 11.4 + C e^-K(0)
60 - 11.4 = C
C= 48.6°
To obtain K
40 = 11.4 + 48.6e^-10k
40 -11.4 = 48.6e^-10k
28.6/48.6 = e^-10k
0.5585 = e^-10k
-10k = ln0.5585
k= ln0.5585/-10
K= 0.0583
Hence, the temperature in 15 minutes;
θ= 11.4 + 48.6e^(-0.0583 × 15)
θ= 31.7°
Answer:
Magnitude of electric field is 1.06 x 
V/m along negative X-direction
Explanation:
Given: initial velocity of proton = u = 3.5 x 
m/s
final velocity of proton = v = 0 m/s
initial point 
= 0.2 m and final point is 
= 0.8 m
According to conservation of energy:
change in in kinetic energy = change in potential energy of proton
⇒
where q and m is the charge and mass of proton E is the electric field , and is the initial and final position of proton
on substituting the respected values we get,
1.023 x 
= 9.6 x 
x E
⇒ E = 1.06 x V/m
external force is opposite to the motion as velocity of proton decreases with distance.
Therefore, magnitude of electric field is 1.06 x V/m along negative X-direction
