A girl exerts a horizontal force of 109 N on a crate with a mass of 31.2 kg. HINT (a) If the crate doesn't move, what's the magn
1 answer:
Answer:
(a) Magnitude of static friction force is 109 N
(b) Minimum possible value of static friction is 0.356
Solution:
As per the question;
Horizontal force exerted by the girl, F = 109 N
Mass of the crate, m = 31.2 kg
Now,
(a) To calculate the magnitude of static friction force:
Since, the crate is at rest, the forces on the crate are balanced and thus the horizontal force is equal to the frictional force, f:
F = f = 109 N
(b) The maximum possible force of friction between the floor and the crate is given by:
where
N = Normal reaction = mg
Thus
For the crate to remain at rest, The force exerted on the crate must be less than or equal to the maximum force of friction.
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Answer:
the final temperature = 74.33°C
Explanation:
Using the expression Q = mcΔT for the heat transfer and the change in temperature .
Here ;
Q = heat transfer
m = mass of substance
c = specific heat
ΔT = the change in temperature
The heat Q required to change the phase of a sample mass m is:
Q = m
where;
is the latent heat of vaporization.
From the question ;
Let M represent the mass of the coffee that remains after evaporation is:
ΔT =
where;
m = 2.50 g
M = (240 - 2.50) g = 237.5 g
= 539 kcal/kg
c = 1.00kcal/kg. °C
ΔT =
ΔT = 5.67°C
The final temperature of the coffee is:
ΔT
where ;
= initial temperature = 80 °C
= (80 - 5.67)°C
= 74.33°C
Thus; the final temperature = 74.33°C
Answer:
Explanation:
As we know that the radius of the circular motion is given as
time period of the motion is given as
now we know that it is moving with uniform speed
so it is given as
now plug in all data
By definition, speed is the integral of acceleration with respect to time.
We have then:
As the acceleration is constant, then integrating we have:
Where,
vo: constant of integration that corresponds to the initial velocity
We observe then that the speed varies linearly when the acceleration is constant .
Therefore, for constant acceleration, the velocity is changing.
Answer:
an object with a constant acceleration always have:
A. changing velocity