Home/Class 12/Physics/

Question and Answer

Suppose while sitting in a parked car, you notice a jogger approaching towards you in the side view mirror of  \(R=2\text{ m }\) . If the jogger is running at a speed of  \(5\text{ ms}^{-1}\) , how fast the image of the jogger appears to move when the jogger is  \(39\text{ m }\)  away.

Answer

\(\frac{1}{280}m/s\)
To Keep Reading This Answer, Download the App
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play
To Keep Reading This Answer, Download the App
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play

Solution

Given,
Radius of curvature  \(R=2\text{ m }\) 
Initial distance of jogger,  \(u_1=-39\text{ m }\) 
After\(1s\), displacement of jogger
 \(u_2=-39+5\)  (As jogger is running at a speed of 5m/s)
 \(=-34\text{ m }\) 
Focal length,\(f=\frac R 2\) 
 \(=\frac 2 2\) 
 \(=1m\) 
By mirror formulae,
\(\frac{1}{v}+\frac{1}{u}=\frac{1}{f}\)
 \(\frac 1 v=\frac 1 f-\frac 1 u\) 
 \(\Rightarrow v=\frac{\mathit{fu}}{u-f}\) 
For   \(u_1=-39\text{ m}\)
Position of image,
 \(v_1=\frac{fu_1}{u_1-f}\) 
 \(=\frac{1\times (-39)}{-39-1}\) 
 \(=\dfrac{39}{40}\;\text{m}\) 
For  \(u_2=-34\text{ m }\)
Position of image,
 \(v_2=\frac{fu_2}{u_2-f}\) 
 \(=\frac{1\times \left. \left(−34\right)\right. }{−34−1}\) 
 \(=\frac{34}{35}\) 
Speed of image\(=\frac{distance\;covered}{time\;taken}\)
 \(V_i=\frac{v_1-v_2} 1\) 
 \(=\frac{39}{40}-\frac{34}{35}\) 
 \(=\frac 1{280}\text{ms}^{-1}\) 
To Keep Reading This Solution, Download the APP
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play
To Keep Reading This Solution, Download the APP
4.6
star pngstar pngstar pngstar pngstar png
Review from Google Play
Correct40
Incorrect0
Watch More Related Solutions
In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Assertion: Benzyl bromide when kept in acetone-water, produces benzyl alcohol.
Reason : The reaction follows \( {S}_{N}2\)mechanism.
Can a process on an ideal gas be both adiabatic and isothermal?
Solve the following for \( x\):
\(\sin ^{-1}(6x)+\sin ^{-1}(6\sqrt {3}x)=-\frac {\pi }{2}\)
A hot liquid is kept in a big room. Its temperature is plotted as a function of time. Which of the following curves may represent the plot?

Write the IUPAC name of following compound:

Find the solubility product of a saturated solution of \(Ag_{2}CrO_{4}\) in water at 298K if the emf of the cell \(Ag|Ag^{+}\) (saturated. \(AgCrO_{4}\) solution.) \(||Ag^{+}(0.1M)|Ag\) is \(0.164V\) at 298 K.
Solve for \(x\): \(\sin ^{-1}x+\sin ^{-1}(1-x)=\cos ^{-1}x\)
Solve the following for x
\(\sin ^{-1}(\frac {5}{x})+\sin ^{-1}(\frac {12}{x})=\frac {\pi }{2}\)
The earth takes \(24\;\text{h}\)  to rotate once about its axis. How much time does the sun take to shift by \(1^0\)  when viewed from the earth?
Consider the bcc unit cells of the solids \(1\) and \(2\) with the position of atoms as shown below. The radius of atom \(B\) is twice that of atom \(A\). The unit cell edge length is \(50\% \) more in solid \(2\) than in \(1\). What is the approximate packing efficiency in solid \(2\)?
( )
A. \(65\%\)
B. \(90\%\)
C. \(75\%\)
D. \(45\%\)

Load More