When a object is at rest, what is it’s speed??
2 answers:
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Answer:
(a) 62.5 m
(b) 7.14 s
Explanation:
initial speed, u = 35 m/s
g = 9.8 m/s^2
(a) Let the rocket raises upto height h and at maximum height the speed is zero.
Use third equation of motion
h = 62.5 m
Thus, the rocket goes upto a height of 62.5 m.
(b) Let the rocket takes time t to reach to maximum height.
By use of first equation of motion
v = u + at
0 = 35 - 9.8 t
t = 3.57 s
The total time spent by the rocket in air = 2 t = 2 x 3.57 = 7.14 second.
Answer:
Temperature of the gas molecules is 7.96 x 10⁴ K
Explanation:
Given :
Ions accelerated through voltage, V = 10.3 volts
The work done to change the position of singly charged gas ions is given by the relation :
W = q x V
Here q is charge of the ions and its value is 1.6 x 10⁻¹⁹ C.
Average kinetic energy of gas molecules is given by the relation:
K.E. =
Here T is temperature and k is Boltzmann constant and its value is 1.38 x 10⁻²³ J/K.
According to the problem, the average kinetic energy of gas is equal to the work done to move the singly charged ions, i.e. ,
K.E. = W
Rearrange the above equation in terms of T :
Substitute the suitable values in the above equation.
T = 7.96 x 10⁴ K