its the the first one u said
Answer: The energy absorbed by the reaction from the water is 996 Joules.
Explanation:
Energy absorbed by the reaction or energy lost by the water to the reaction,Q.
Mass of the the reaction ,m = 60 g
Specific heat of water = c = 4.15 J\g ^oC
Change is temperature=

Negative sigh indicates that energy was given by the water to the reaction.
The energy absorbed by the reaction from the water is 996 Joules.
Answer:
The velocity of the arrow after 3 seconds is 30.02 m/s.
Explanation:
It is given that,
An arrow is shot upward on the moon with velocity of 35 m/s, its height after t seconds is given by the equation:

We know that the rate of change of displacement is equal to the velocity of an object.

Velocity of the arrow after 3 seconds will be :

So, the velocity of the arrow after 3 seconds is 30.02 m/s. Hence, this is the required solution.
Answer:
a. The moment of the 4 N force is 16 N·m clockwise
b. The moment of the 6 N force is 12 N·m anticlockwise
Explanation:
In the figure, we have;
The distance from the point 'O', to the 6 N force = 2 m
The position of the 6 N force relative to the point 'O' = To the left of 'O'
The distance from the point 'O', to the 4 N force = 4 m
The position of the 4 N force relative to the point 'O' = To the right of 'O'
a. The moment of a force about a point, M = The force, F × The perpendicular distance of the force from the point
a. The moment of the 4 N force = 4 N × 4 m = 16 N·m clockwise
b. The moment of the 6 N force = 6 N × 2 m = 12 N·m anticlockwise.