Question

a particle of mass 1kg is moving on a curved path with constant speed 10m/s. Which of the following statement is/are correct.


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Answer 1

Answer :- a) The kinetic energy at time t is 50 J.

Explanation

Given, Mass of the object = 1 kg.

Particle is moving with a constant speed of 10 m/s.

Kinetic energy = $\dfrac{1}{2}mv^2$

$\implies \: \: K.E. = \: \dfrac{1}{2} \times 1 \times (10)^2 \\ \\ \\ = \: 50 J$

• Kinetic energy is dependent on speed only. Since, the speed is constant here. Kinetic energy will be constant.

• Kinetic energy of any particle can never be negative. Therefore, we can discard option c) without looking at the question.

Answer 2

➡ Refer the attachment for explanation.

✅ Option - 1 is correct.

Gɪᴠᴇɴ :

• Mass of a particle is 1 kg.

• The particle is moving with a constant speed, i.e. 10 m/s.

Sᴛᴇᴘ-ʙʏ-sᴛᴇᴘ Exᴘʟᴀɴᴀᴛɪᴏɴ :

We know that,

↝ Kinetic energy of a particle moving with constant speed on a curved path is,

$\red\bigstar\:\bigg\{\:\bf\purple{K.E\:=\:\dfrac{1}{2}\:m\:v^2\:}\:\bigg\}\:\red\bigstar$

Where,

• m is the mass of the particle, i.e. 1 kg.

• v is the speed, i.e. 10 m/s.

➙ $\bf{Kinetic\:energy\:=\:\dfrac{1}{2}\times{1}\times{(10)^2}\:}$

➙ $\bf{Kinetic\:energy\:=\:\dfrac{1}{2}\times{100}\:}$

➙ $\bf\blue{Kinetic\:energy\:=\:50\:J}$

✯ As we know that if speed of a particle is constant then the kinetic energy is also a constant at any inśtant.

$\Large\bf{\therefore}$ Option - 1 is correct.

✯ Kinetic energy of a particle does not depend upon time period.

$\Large\bf{\therefore}$ Option - 2 is incorrect.

✯ Kinetic energy can never be negative in case of circular motion.

$\Large\bf{\therefore}$ Option - 3 is incorrect.