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QJEEM23Ph8e60: JEE Main 2023 Physics - Class 11 JEEM23Ph8e60 Solution: A ball is thrown vertically upward with an initial velocity of…

A ball is thrown vertically upward with an initial velocity of 150 m/s150 \mathrm{~m} / \mathrm{s} . The ratio of velocity after 3 s3 \mathrm{~s} and 5 s5 \mathrm{~s} is x+1x\frac{x+1}{x} . The value of xx is ___________.

{\left\{\right. take, g=10 m/s2}\left.g=10 \mathrm{~m} / \mathrm{s}^{2}\right\}

Multiple Choice Options

  • A −5-5
  • B 10
  • C 5
  • D 6

Step-by-Step Verified Solution

To solve this problem, we can use the following equation of motion for the vertical velocity at any given time tt :

v=u−gtv = u - gt

Where:

- vv is the final velocity at time tt

- uu is the initial velocity (150 m/s)

- gg is the acceleration due to gravity (10 m/s²)

- tt is the time in seconds

First, we need to find the velocities at t=3 st = 3 \mathrm{~s} and t=5 st = 5 \mathrm{~s} .

For t=3 st = 3 \mathrm{~s} :

v3=150−(10)(3)=150−30=120 m/sv_3 = 150 - (10)(3) = 150 - 30 = 120 \mathrm{~m} / \mathrm{s}

For t=5 st = 5 \mathrm{~s} :

v5=150−(10)(5)=150−50=100 m/sv_5 = 150 - (10)(5) = 150 - 50 = 100 \mathrm{~m} / \mathrm{s}

Now we need to find the ratio of these velocities:

v3v5=120100=65=x+1x\frac{v_3}{v_5} = \frac{120}{100} = \frac{6}{5} = \frac{x + 1}{x}

Next, we can set up an equation to find the value of xx :

65=x+1x\frac{6}{5} = \frac{x + 1}{x}

Now, we can solve for xx :

6x=5(x+1)6x = 5(x + 1)

6x=5x+56x = 5x + 5

x=5x = 5

The value of xx is 5.

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