Answer:

Explanation:
From the question we are told that
Weight of fireman 
Pole distance 
Final speed is 
Generally the equation for velocity is mathematically represented as

Therefore Acceleration a
Generally the equation for Frictional force
is mathematically given as



Therefore

consider the motion along the X-direction
X = horizontal displacement = 80 m
= initial velocity along the x-direction = v Cos60
t = time of travel
using the equation
X =
t
80 = (v Cos60) (t)
t = 160/v eq-1
consider the motion in vertical direction :
Y = vertical displacement = 20 m
= initial velocity in Y-direction = v Sin60
a = acceleration = - 9.8 m/s²
t = time of travel = 160/v
using the equation
Y =
t + (0.5) a t²
20 = (v Sin60) (160/v) + (0.5) (- 9.8) (160/v)²
v = 32.5 m/s
Answer: Option (d) is the correct answer.
Explanation:
A chemical reaction in which heat energy is liberated is known as an exothermic reaction.
For example, 
In an exothermic reaction, energy of reactants is more than the energy of products.
This means that potential energy of products is less than the potential energy of reactants.
Thus, we can conclude that in the reaction
, the potential energy of the products is less than that of the reactant.
In scientific inquiry, hypothesis acts as the road map that guide the researcher and show him how to go about his scientific investigation. Hypothesis provides a testable explanation for an observation and serves as the starting point for the scientific investigation.