A ball is thrown upwards with initial velocity 20 m/s. After reaching maximum height, on the way down it strikes a bird which is 10 m above the ground. What is the velocity of the ball when it hits the bird

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.