Answer:
831.4 J
Explanation:
Info given:
mass adult: 82.5kg
mass child: 14.7kg
height of wall: 1.25m
g = 9.81m/s^2
PE = mgh
For adult:
mgh = (82.5kg)(9.81m/s^2)(1.25m) = 1011.65 J
For child:
mgh = (14.7kg)(9.81m/s^2)(1.25m) = 180.25 J
Difference in PE: 1011.65 J - 180.25 J = 831.4 J
Answer:
The velocity of the astronaut is, v = - 0.36 m/s
Explanation:
Given data,
The mass of the astronaut, M = 84 kg
The mass of the gas expelled by the thruster, m = 35 g
= 0.035 g
The velocity of the gas expelled, v = 875 m/s
According to the conservation of momentum,
MV + mv = 0
V = - mv / M
Substituting the values,
V = - 0.035 x 875 / 84
= - 0.36 m/s
The negative sign in the velocity indicates the astronaut moves opposite to the direction of velocity of gas.
Hence, the velocity of the astronaut is, v = - 0.36 m/s
Answer:
30 cm
Explanation:
Hi! Lets find the angles for the first and second order maxima
The first order maximum will occur for Ф=0
The second order maximum will satisfy the following relationship:
sinФ = λ/d
Where λ = 600 x 10^-9 m and d = 5 x 10^-5 m
Therefore:
sinФ = 0.012
And the vertical distance bewteen the first and second will be given by:
l = (2.5 m) tanФ
But since 2.5 m>>0.05 mm ; sinФ≈tanФ
Therefore:
l = (2.5 m) sinФ
l = 0.03 m = 30 cm
Explanation :
We know that the resistance of the wire is given by :
Where
is the resistivity
l is the length of the wire
A is the area of the wire.
Another factor on which the resistance of wire depends is temperature. It is given by :
![R=R_{ref}[1+\alpha (T-T_{ref})]](https://tex.z-dn.net/?f=R%3DR_%7Bref%7D%5B1%2B%5Calpha%20%28T-T_%7Bref%7D%29%5D)
So, it is clear that the resistance of the wire is directly proportional to the temperature. It we want to decrease the resistance of the piece, its temperature should be decreased.
So, the correct option is (3) " decreasing the wire’s temperature ".
Assuming you mean "x" to be "horizontal" and "y" to be "vertical", the 1.20 m is y.
The initial vertical velocity is 0.
How long does it take for something to fall 1.20 m from rest? That's the time the mug is in the air.
The initial vertical velocity is 0. How long does it take for something to fall 1.20 m from rest? That's the time the mug is in the air.
The initial horizontal velocity is 1.50 m/s. Ignoring air resistance, that's going to be constant. Once you know how long the mug is in the air, multiply that time by 1.50 m/s and you've got the horizontal distance from the end of the bar, and you're done.
