Question

15. A stone is thrown vertically upward with an initial velocity of
40 m/s. Taking g = 10 m/s², find the maximum height reached
by the stone. What is the net displacement and the total
distance covered by the stone?​

Answer 1

Answer:

NSWER

Answer is B.

Given that Initial velocity, u = 40 m/s, Final velocity, v = 0 m/s.

Acceleration due to gravity, g = 10m/s2(downward motion).

Maximum height, s = H.

As the body is thrown upward a = -g the relation v2=u2−2as gives v2=u2−2aH, we have,

H = 2gu2−v2=2(10m/s2)40m/s2−02=201600=80m.

If a stone is thrown vertically upward, it returns to its initial position after achieving maximum height.

so, the net displacement = Difference of positions between initial and final positions = 0.

Total distance covered = 80 m + 80 m = 160 m.

Hence, the displacement is 0 and the total distance covered is 160 m.

Explanation:

Please follow me.

Answer 2

$\bigstar\huge\mathtt{\red{Solution :}}$

As per the given question ,

The initial velocity of the stone =40 m/s

Acceleration due to gravity = 10 m/s^2

Final velocity of the stone = 0 m/s (The velocity of an object at the highest point is always zero )

Now in order to find height let us use  the third equation of motion ,

we know that ,

$\bigstar\boxed{\mathtt{v^{2} =u^{2}\underline{ +}2gh}}$

here,

• v = final velocity
• u= initial velocity
• g= acceleration due to gravity
• h = height

Now substituting the given values in  the above equation we get ,

$\rightarrow\mathtt{0= (40)^{2} - 2 \times 10 \times h }$

$\rightarrow\mathtt{(40)^{2} = 20h}$

$\rightarrow\mathtt{h= \dfrac{1600}{20}}$

$\rightarrow\mathtt{\blue{h= 80\:m}}$

The maximum height reached by the stone is 80 m .

_______________________

• Distance is scalar quantity (magnitude only )
• Distance is the actual path traveled by the stone during its flight

Total distance covered by the stone

$\rightarrow\mathtt{s = h + h }$

$\rightarrow\mathtt{s =80 + 80 }$

$\rightarrow\mathtt{\orange{s = 160 m}}$

The total distance covered by the stone is 160 m.

_________________________

• Displacement is a vector quantity (magnitude as well as direction )
• It doesn't depend upon the path traveled by the object it depends only about the initial and final position of the object

As the initial and the final position of the stone is the same the net displacement is zero

OR

$\rightarrow\mathtt{d = h +(- h) }$

$\rightarrow\mathtt{d=80 - 80 }$

$\rightarrow\mathtt{\pink{d = 0 m}}$

Net displacement of the stone is 0 m .