let here North direction is along +Y and South direction is along -Y
similarly East direction is towards +X and west direction is towards -X
now it is given that
first it moves 235 km north

then it moves back 126 km south

then again he moves north

now the total displacement is given as


so final displacement of train is 154 km North
Answer:
(a) Current flowing through truck battery is 180 A
(b) Time taken in calculator is 333.33 s
Explanation:
(a) Given:
The charge on the truck battery,q = 720 C
Time, t = 4.00 s
Consider I be the current flowing through truck battery.
The relation between current, charge and time is:
I = q/t
Substitute the suitable values in the above equation.

I = 180 A
(b) Given:
The charge on the calculator,q = 7.00 C
The current flowing through calculator, I = 0.3 mA = 0.3 x 10⁻³ A
Consider t be the time.
The relation between current, charge and time is:
t = q/I
Substitute the suitable values in the above equation.

I = 333.33 s
Answer:
W = 30 J
Explanation:
given,
Work done = 10 J
Stretch of spring, x = 0.1 m
We know,
dW = F .dx
we know, F = k x


![W = k[\dfrac{x^2}{2}]_0^{0.1}](https://tex.z-dn.net/?f=W%20%3D%20k%5B%5Cdfrac%7Bx%5E2%7D%7B2%7D%5D_0%5E%7B0.1%7D)

k = 2000
now, calculating Work done by the spring when it stretched to 0.2 m from 0.1 m.

![W = 2000 [\dfrac{x^2}{2}]_{0.1}^{0.2} dx](https://tex.z-dn.net/?f=W%20%3D%202000%20%5B%5Cdfrac%7Bx%5E2%7D%7B2%7D%5D_%7B0.1%7D%5E%7B0.2%7D%20dx)
W = 1000 x 0.03
W = 30 J
Hence, work done is equal to 30 J.
Answer:
First Kepler law states that <em><u>Each</u></em><em><u> </u></em><em><u>planet</u></em><em><u> </u></em><em><u>describes</u></em><em><u> </u></em><em><u>an</u></em><em><u> </u></em><em><u>ellipsoidal</u></em><em><u> </u></em><em><u>motion</u></em><em><u> </u></em><em><u>about</u></em><em><u> </u></em><em><u>the</u></em><em><u> </u></em><em><u>sun</u></em><em><u> </u></em><em><u>as</u></em><em><u> </u></em><em><u>its</u></em><em><u> </u></em><em><u>single</u></em><em><u> </u></em><em><u>focus</u></em><em><u>.</u></em>
Second Kepler law states that <em><u>A</u></em><em><u>n</u></em><em><u> </u></em><em><u>i</u></em><em><u>m</u></em><em><u>a</u></em><em><u>g</u></em><em><u>i</u></em><em><u>n</u></em><em><u>a</u></em><em><u>r</u></em><em><u>y</u></em><em><u> </u></em><em><u>l</u></em><em><u>i</u></em><em><u>n</u></em><em><u>e</u></em><em><u> </u></em><em><u>j</u></em><em><u>o</u></em><em><u>i</u></em><em><u>n</u></em><em><u>i</u></em><em><u>n</u></em><em><u>g</u></em><em><u> </u></em><em><u>a</u></em><em><u> </u></em><em><u>planet</u></em><em><u> </u></em><em><u>t</u></em><em><u>o</u></em><em><u> </u></em><em><u>t</u></em><em><u>h</u></em><em><u>e</u></em><em><u> </u></em><em><u>Sun</u></em><em><u> </u></em><em><u>sweeps</u></em><em><u> </u></em><em><u>out</u></em><em><u> </u></em><em><u>equal</u></em><em><u> </u></em><em><u>areas</u></em><em><u> </u></em><em><u>in</u></em><em><u> </u></em><em><u>equal</u></em><em><u> </u></em><em><u>time</u></em><em><u> </u></em><em><u>intervals</u></em><em><u>.</u></em>
Third Kepler law states that <em><u>The</u></em><em><u> </u></em><em><u>squares</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>period</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>revolution</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>the</u></em><em><u> </u></em><em><u>planet</u></em><em><u> </u></em><em><u>around</u></em><em><u> </u></em><em><u>the</u></em><em><u> </u></em><em><u>sun</u></em><em><u> </u></em><em><u>are</u></em><em><u> </u></em><em><u>proportional</u></em><em><u> </u></em><em><u>to</u></em><em><u> </u></em><em><u>the</u></em><em><u> </u></em><em><u>cubes</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>mean</u></em><em><u> </u></em><em><u>distance</u></em><em><u> </u></em><em><u>between</u></em><em><u> </u></em><em><u>the</u></em><em><u> </u></em><em><u>planet</u></em><em><u> </u></em><em><u>and</u></em><em><u> </u></em><em><u>the</u></em><em><u> </u></em><em><u>sun</u></em><em><u>.</u></em>
Weightlessness is the condition where the body has zero gravity ( its acceleration is equal to the acceleration due to gravity )
