A paper weight is dropped from the roof of a block of multi storey flats. each storey being 3 metre high. it passes the ceiling of the 20th storey at 30m/s. if g=10m/s2, how many storeys does the flat have?

What is the net force needed to lift a full grocery sack (weighing 210N) uniformly?

What is convection? Does it only affect plate tectonics?

Suppose a well-designed optical instrument is composed of two converging lenses separated by 14 cm. The focal lengths of the lenses are 0.60 and 4.5 cm. Is the instrument a microscope or a telescope

A motorbike travels 45 miles in 15 minutes what is its speed

How does the sun drive convection currents in the ocean and in the atmosphere

In what way would a digital thermometer be preferable to those from a liquid-based thermometer? Digital thermometer readings are easier to use when performing calculations.

Why does the core of the sun contain more helium and less hydrogen than the surface of the sun?

What happens to a light ray passing through the center of a lens?

A spider crawling across a table leaps onto a magazine blocking its path. The initial velocity of the spider is 0.870 m/s at an angle of 35.0° above the table, and it lands on the magazine 0.0770s after leaving the table. Ignore air resistance.

A force of 5 N accelerates an object. The object's mass is 50 g. What is the acceleration of the object? (Formula: F=ma)