Answer:
2.465Ns;1.76N
Explanation:
From Newton's Second Law:
There is a conservation of Momentum hence:
Momentum before the impact equals that after the impact.
Hence.
1. The Impulse is same as the change in Momentum which is;
0.145 ×17 =2.465Ns { note: 145g in kg is 0.145}
2. From Newton's third Law; force is the rate of change of impulse expressed mathematically as;
F = m×v / t
Where m×v is impulse and t is time given.
F = 2.465/ 1.4 = 1.76N
the 4 resistor wired in series is equal to 0.639 ohms
Answer:
a
Generally from third equation of motion we have that
![v^2 = u^2 + 2a[s_i - s_f]](https://tex.z-dn.net/?f=v%5E2%20%3D%20%20u%5E2%20%2B%202a%5Bs_i%20-%20s_f%5D%20)
Here v is the final speed of the car
u is the initial speed of the car which is zero
is the initial position of the car which is certain height H
is the final position of the car which is zero meters (i.e the ground)
a is the acceleration due to gravity which is g
So
=> ![v = \sqrt{ 2 g H}](https://tex.z-dn.net/?f=v%20%20%3D%20%20%5Csqrt%7B%202%20g%20H%7D)
b
Explanation:
Generally from third equation of motion we have that
![v^2 = u^2 + 2a[s_i - s_f]](https://tex.z-dn.net/?f=v%5E2%20%3D%20%20u%5E2%20%2B%202a%5Bs_i%20-%20s_f%5D%20)
Here v is the final speed of the car
u is the initial speed of the car which is zero
is the initial position of the car which is certain height H
is the final position of the car which is zero meters (i.e the ground)
a is the acceleration due to gravity which is g
So
=> ![v = \sqrt{ 2 g H}](https://tex.z-dn.net/?f=v%20%20%3D%20%20%5Csqrt%7B%202%20g%20H%7D)
When
we have that
![13.9 = \sqrt{ 2 g H}](https://tex.z-dn.net/?f=13.9%20%20%3D%20%20%5Csqrt%7B%202%20g%20H%7D)
=> ![H = \frac{13.9^2}{2 * 9.8}](https://tex.z-dn.net/?f=H%20%20%3D%20%20%5Cfrac%7B13.9%5E2%7D%7B2%20%2A%20%209.8%7D)
=>
As we know by the first law of thermodynamics
![Q = \Delta U + W](https://tex.z-dn.net/?f=Q%20%3D%20%5CDelta%20U%20%2B%20W)
here we know that
Q = heat given to the system
![\Delta U = U_f - U_i](https://tex.z-dn.net/?f=%5CDelta%20U%20%3D%20U_f%20-%20U_i)
W = work done by the system
now here we can say
![\Delta U = 180 - 78 = 102 J](https://tex.z-dn.net/?f=%5CDelta%20U%20%3D%20180%20-%2078%20%3D%20102%20J)
![W = 64 J](https://tex.z-dn.net/?f=W%20%3D%2064%20J)
now we can say that heat will be given as
![Q = 64 + 102 = 166 J](https://tex.z-dn.net/?f=Q%20%3D%2064%20%2B%20102%20%3D%20166%20J)
now here we can say that Jin does the error in his first step while calculation of change in internal energy as he had to subtract it while he added the two energy
So best describe Jin's Error is
<em>B )For step 1, he should have subtracted 78 J from 180 J to find the change in internal energy. </em>