Question :
If a body acquires a charge of -0.02 C, has it gained or lost electrons? Many?
Solution :
We know, charge gained is shown by negative sign.
Since, charged acquired is given as -0.02 C .
Therefore, it is body has gained electrons.
Now, number of electrons is given by :
![n = \dfrac{net\ charge}{charge \ on \ one \ electron}\\\\n = \dfrac{-0.02}{-1.60 \times 10^{-19}}\\\\n = 1.25\times 10^{17}](https://tex.z-dn.net/?f=n%20%3D%20%5Cdfrac%7Bnet%5C%20charge%7D%7Bcharge%20%5C%20%20on%20%5C%20one%20%5C%20%20electron%7D%5C%5C%5C%5Cn%20%3D%20%5Cdfrac%7B-0.02%7D%7B-1.60%20%5Ctimes%2010%5E%7B-19%7D%7D%5C%5C%5C%5Cn%20%3D%201.25%5Ctimes%2010%5E%7B17%7D)
Hence, this is the required solution.
Answer:
98N and 147N
Explanation:
We have the following information:
![m=50kg\\\mu_s =0.4\\\mu_k = 0.2\\F=140N](https://tex.z-dn.net/?f=m%3D50kg%5C%5C%5Cmu_s%20%3D0.4%5C%5C%5Cmu_k%20%3D%200.2%5C%5CF%3D140N)
We can find the static fricton force as follow,
![F=\mu_s * N](https://tex.z-dn.net/?f=F%3D%5Cmu_s%20%2A%20N)
Where N is the normal force (mg)
![F=0.3*50*9.8\\F=147N](https://tex.z-dn.net/?f=F%3D0.3%2A50%2A9.8%5C%5CF%3D147N)
Static friction force at 147N is greater than the force applied hence body does not move.
![F=\mu_k N = 0.2*50*9.8= 98N](https://tex.z-dn.net/?f=F%3D%5Cmu_k%20N%20%3D%200.2%2A50%2A9.8%3D%2098N)
Answer:
is the rock's speed.
Explanation:
Momentum is defined as motion possessed by the moving body's mass. Mathematically it a product of mas and velocity of the body.
![Momentum(P)=Mass(m)\times velocity(v)](https://tex.z-dn.net/?f=Momentum%28P%29%3DMass%28m%29%5Ctimes%20velocity%28v%29)
Given : Mass of rock = m = 1.45 kg
Velocity of the rock = v
Momentum of the rock = P =![1.93\times 10^8 kg m/s](https://tex.z-dn.net/?f=1.93%5Ctimes%2010%5E8%20kg%20m%2Fs)
![1.93\times 10^8 kg m/s=1.45 kg\times v](https://tex.z-dn.net/?f=1.93%5Ctimes%2010%5E8%20kg%20m%2Fs%3D1.45%20kg%5Ctimes%20v)
![v=\frac{1.93\times 10^8 kg m/s}{1.45 kg}=1.33\times 10^8 m/s](https://tex.z-dn.net/?f=v%3D%5Cfrac%7B1.93%5Ctimes%2010%5E8%20kg%20m%2Fs%7D%7B1.45%20kg%7D%3D1.33%5Ctimes%2010%5E8%20m%2Fs)
is the rock's speed.