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vo = 25 m/sec
<span>vf = 0 m/sec </span>
<span>Fμ = 7100 N (Force due to friction) </span>
<span>Fg = 14700 N </span>
<span>With the force due to gravity, you can find the mass of the car: </span>
<span>F = ma </span>
<span>14700 N = m (9.8 m/sec²) </span>
<span>m = 1500 kg </span>
<span>Now, we can use the equation again to find the deacceleration due to friction: </span>
<span>F = ma </span>
<span>7100 N = (1500 kg) a </span>
<span>a = 4.73333333333 m/sec² </span>
<span>And now, we can use a velocity formula to find the distance traveled: </span>
<span>vf² = vo² + 2a∆d </span>
<span>0 = (25 m/sec)² + 2 (-4.73333333333 m/sec²) ∆d </span>
<span>0 = 625 m²/sec² + (-9.466666666667 m/sec²) ∆d </span>
<span>-625 m²/sec² = (-9.466666666667 m/sec²) ∆d </span>
<span>∆d = 66.0211267605634 m </span>
<span>∆d = 66.02 m</span>
Answer: 
The linear momentum
is given by the following equation:
(1)
Where
is the mass and
the velocity.
On the other hand, the kinetic energy
is given by:
(2)
Which is the same as:

Now, if we double the kinetic energy, equation (2) changes to:
(3)
So, if we want to obtain the kinetic energy as shown in (3), the only option that works is increasing momentum by a factor of
or
:
Applying this in (2):


>>>As we can see, this equation is the same as equation (3)
Therefore, the correct answer is B
Answer:
-929.5Joules
Explanation:
To get the work done by sam, we will calculate the kinetic energy of sam expressed as;
KE = 1/2mv²
m is the mass = 1100kg
v is the velocity = 1.3m/s
KE = 1/2(1100)(1.3)²
KE = 550(1.69)
KE = 929.5Joules
Since Sam is opposing the direction of movement, work done by him will be a negative work i.e -929.5Joules
Answer:
Under assumption that all food energy that needs the horse is transformed into work, then the horse needs approximately 3 megajoules of food energy to work for 1 hour.
Explanation:
Since horse is working steadily, the power experimented by the horse (
), measured in watts, is at constant rate. Then, the work needed by the horse (
), measured in joules, is equal to that power multiplied by time (
), measured in seconds. That is:
(1)
If we know that
and
, then the work needed for the horse is:



Under assumption that all food energy that needs the horse is transformed into work, then the horse needs approximately 3 megajoules of food energy to work for 1 hour.