A force of 49 Newtons is applied to a rock, which causes it to be lifted 2 meters in 5 seconds. How much power is
exerted during this time?

19.6Watts

Explanation:

Given parameters:

Force applied  = 49N

Distance  = 2m

Time  = 5s

Unknown:

Power  = ?

Solution:

Power is the rate at which work is being done;

   Power  =

Work done  = force x distance  = 49 x 2 = 98J

So;

      Power  =  = 19.6Watts

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

the answer would be c