If the angle is either 0 or 180, that means that there is either negative or positive work, so A and D are not correct.
If the angle is 45, then there is still some work involved.
The only option where there is no work done by a force is B. when the angle is between the force and displacement is 90.
The correct options are as follows:
1. A.
A synthesis reaction is a type of reaction in which two or more reactants combine together to form only one product. Synthesis reaction always release energy in form of light and heat, therefore, they are usually exothermic reactions. In the option given in A, nitrogen and nitrogen combine together to form ammonia; this is a synthesis reaction.
2. D
A radioactive half life refers to the amount of time it will take for half of an original radioactive isotope to decay.
In the question given above, the half life of the element is 1000. Thus, in 1000 years only half of the original amount will remain. In another 1000 years only 1/4 of the original amount will remain and in another 1000 years only 1/8 of the original amount will remain. Therefore, it will take 3 half lives before 1/8 of the original sample remain.<span />
Answer:
Yes
Explanation: Yes it depends on what kind of animal but yes it can help
Answer:
The correct option is a.
Explanation:
125 kPa
125kpa - 2x 4x x
Total pressure after reaction = 176 kPa
125 kPa - 2x + 4x + x = 176 kPa
x = 17
125 kpa - 2x = 125 kPa - 2(17) = 91 kPa
Initial pressure of the dinitrogen pentoxide ,(at t=0) =
Final pressure of the dinitrogen pentoxide, (at t = t) = P = 91 kPa
The rate constant is = 
It will take 113 minutes for the total pressure to reach 176 kPa.
