What is the acceleration of the object?<br> m/s2

John argues that energy is not conserved because when someone presses the brakes in a moving car, kinetic energy is lost. What s

babunello [35]

kinetic energy is converted into elastic potential energy stored in the brakes.

7 0

3 years ago

An electron and an antielectron (positron) each have a rest energy of 0.511 MeV , or approximately 8.2×10−14 J . When an electro

Mademuasel [1]

Answer:

Explanation:

Photon is also a particle . Hence when two particles like electron and positron annihilate to get completely changed to photons , a minimum of two photons of equal and opposite momentum and energy are produced flying in opposite direction to conserve momentum and energy . Each photon will have same energy equal to 511 keV . It is so to conserve momentum and energy. Initially total momentum was zero so finally too total momentum should be zero.

8 0

3 years ago

A small metal ball is suspended from the ceiling by a thread of negligible mass. The ball is then set in motion in a horizontal

Gemiola [76]

Answer:

Time taken, $T=2\pi \sqrt{\dfrac{l\ cos\theta}{g}}$

Explanation:

It is given that, a small metal ball is suspended from the ceiling by a thread of negligible mass. The ball is then set in motion in a horizontal circle so that the thread’s trajectory describes a cone as shown in attached figure.

From the figure,

The sum of forces in y direction is :

$T\ cos\theta-mg=0$