Answer:
B.7.5m/s2
Explanation:
average acceleration=change invelocity/time taken
a=(60-30)/4
=7.5m/s2
They are hard to detect because they have no electric charge
<h2>
Answer:g=9.79,A object of mass
at the surface of earth experiences a force
</h2>
Explanation:
Let be the mass of earth.
Let be the radius of earth.
Let be the universal gravitational constant.
Given,
Let be the acceleration due to gravity.
Then,
A object of mass at the surface of earth experiences a force