How can i quantified the amount of radon in a particular place?

What is the pressure exerted by a boy weighing 80kg on the ground when he stands on his feet whose area is 200cm2? A. 80 pa B. 1600 pa C. 40,000 pa D. 400 pa

How does energy travel in a mechanical wave? in space in a vacuum in a medium in time I think C

A 92.9 g piece of a silvery gray metal is heated to 178.0∘C, and then quickly transferred into 75.0 mL of water initially at 24.0∘C. After 5 minutes, both the metal and the water have reached the same temperature: 29.7∘C.

Net force f causes mass m1 to accelerate at rate a. a net force of 3f causes mass m2 to accelerate at rate 2a. what is the ratio of mass m1 to mass m2?

How can you tell the difference between and erosion feature and a deposition feature?

A gate in an irrigation canal is constructed in the form of a trapezoid 2 m wide at the bottom, 38 m wide at the top, and 2 m high. It is placed vertically in the canal so that the water just covers the gate.

A machine with a mechanical advantage of 10 is used to produce an output force of 250 newtons. What input force is applied to this machine

Why do you float in space

How does physical change affect the identity of a substance

A scientist pours grape juice on three identical white shirts He then uses three different cleaning products on the shirts and measures how clean they get what is the independent variable in this experiment