suggest only one best method to avoid such a collision if a near earth asteroid of radius 50m strikes the earth surface?

To avoid a collision with a near Earth asteroid of radius 50m, one of the most effective methods is using a kinetic impactor. Here's how it works:

1. Identifying the trajectory: First, astronomers and space agencies closely monitor the trajectory of the asteroid and predict its potential impact location on Earth.

2. Diverting the asteroid: Once identified, a kinetic impactor spacecraft is sent to intercept the asteroid. This spacecraft is designed to physically collide with the asteroid.

3. Impacting the asteroid: The kinetic impactor spacecraft is equipped with a solid mass that is launched at high velocity to strike the asteroid. The idea is to change its trajectory by imparting momentum to the asteroid.

4. Deflecting the asteroid: The impact of the kinetic impactor alters the asteroid's speed and direction. Ideally, this changes the asteroid's course enough to avoid an Earth impact. Even a small deflection over time can be sufficient to prevent collision.

5. Continuous monitoring: After the initial impact, continuous monitoring and precise observations are necessary to ensure that the asteroid trajectory has been altered successfully and that it no longer poses a threat to Earth.

It's important to note that planning and executing such a mission requires advanced space technology, precise calculations, and international cooperation. Initiatives like NASA's Planetary Defense Coordination Office work towards developing and implementing strategies to avoid potential asteroid impacts.