Answer:
A) F = - 8.5 10² N, B) I = 21 N s
Explanation:
A) We can solve this problem using the relationship of momentum and momentum
I = Δp
in this case they indicate that the body rebounds, therefore the exit speed is the same in modulus, but with the opposite direction
v₀ = 8.50 m / s
v_f = -8.50 m / s
F t = m v_f -m v₀
F = 
let's calculate
F = 
F = - 8.5 10² N
B) let's start by calculating the speed with which the ball reaches the ground, let's use the kinematic relations
v² = v₀² - 2g (y- y₀)
as the ball falls its initial velocity is zero (vo = 0) and the height upon reaching the ground is y = 0
v = 
calculate
v = 
v = 14 m / s
to calculate the momentum we use
I = Δp
I = m v_f - mv₀
when it hits the ground its speed drops to zero
we substitute
I = 1.50 (0-14)
I = -21 N s
the negative sign is for the momentum that the ground on the ball, the momentum of the ball on the ground is
I = 21 N s
Answer:
34.17°C
Explanation:
Given:
mass of metal block = 125 g
initial temperature 
= 93.2°C
We know
..................(1)
Q= Quantity of heat
m = mass of the substance
c = specific heat capacity
c = 4.19 for H₂O in 
= change in temperature
Now
The heat lost by metal = The heat gained by the metal
Heat lost by metal = 
Heat gained by the water = 
thus, we have
=
⇒ 
Therefore, the final temperature will be = 34.17°C
Answer:
Explanation:
The strain is defined as the ratio of change of dimension of an object under a force:
where
is the change in length of the object
is the original length of the object
In this problem, we have 
and 
, therefore the strain is
Answer:
The effect of lowering the condenser pressure on different parameters is explained below.
Explanation:
The simple ideal Rankine cycle is shown in figure.
Effect of lowering the condenser pressure on
(a). Pump work input :- By lowering the condenser pressure the pump work increased.
(b) Turbine work output :- By lowering the condenser pressure the turbine work increased.
(c). Heat supplied :- Heat supplied increases.
(d). Heat rejected :- The heat rejected may increased or decreased.
(e). Efficiency :- Cycle efficiency is increased.
(f). Moisture content at turbine exit :- Moisture content increases.
When the ball has left your hand and is flying on its own, its kinetic energy is
KE = (1/2) (mass) (speed²)
KE = (1/2) (0.145 kg) (25 m/s)²
KE = (0.0725 kg) (625 m²/s²)
<em>KE = 45.3 Joules</em>
If the baseball doesn't have rocket engines on it, or a hamster inside running on a treadmill that turns a propeller on the outside, then there's only one other place where that kinetic energy could come from: It MUST have come from the hand that threw the ball. The hand would have needed to do <em>45.3 J</em> of work on the ball before releasing it.
