How many neutrons does element x have if it's atomic number is 31 and it's mass number is 88?

A ripe acorn falls down from a branch with an initial velocity v0 = 0. The acorn's vertical displacement until it hits the ground (neglecting the effects of air) could be derived using

Which is an example of potential energy? a a car driving on the road b a swimmer kicking their legs c a yo-yo in someone's hand d an arrow flying at a target

Identical twin brothers standing on a horizontal bridge each throw a rock straight down into the water below. They throw rocks at exactly the same time but one hits the water before the other.

You use when you hold an object stationary in your outstretched hand. Suggest what happens to the energy that must be supplied to your muscles to keep them contracted

On a cold winter day, the air temperature is 2°c and the wet-bulb temperature is - 1°c. what is the relative humidity at this location?

What is the kinetic energy of a 1,900 kg car moving at 89 km/h?

Why do we study black holes

Calculate the kinetic energy of a charging elephant if its mass is 5,000kg and it moves at 8m/s

Why is a decrease in Earth's ozone harmful to life?

What force does a window washer want acting on him when trying to keep the same position