Answer:
t = 180 / 1.4 = 129 sec (time to swim horizontally across river)
S = 129 sec * V where V is speed of current and S is the distance he will be carried downstream
The problem does not specify V the speed of the river
Answer:
The particle which completes the given equation is :
Explanation:
The given reaction is of a fission reaction:

Total mass on the reactant side is equal to the total mass on the product side:
239 + 1 = 100 +A+ 2
A = 138
Sum of atomic numbers on the reactant side is equal to the sum of atomic number on the product side:
94 + 1(0) = 40 + Z + 2(0)
Z = 54
So atomic number 54 id of Xenon.
The particle which completes the given equation is :

Explanation:
equating the parameters into the formula, it's gonna be
= ½ × 60 × 20²
= ½ × 60 × 400
= ½ × 24000
K.E = 12000J
the mass number minus the atomic number
Carbon is the answer to the problem