A 8.0 n force acts on a 0.70-kg object for 0.50 seconds. by how much does the object's momentum change (in kg-m/s)? (never inclu
1 answer:
For Newton's second law, the force applied to an object is equal to the product between the mass of the object and its acceleration:
Rewriting the acceleration as the increment of velocity
in a time 
: 
, F becomes
But given the definition of momentum:
, then 
represents the momentum change. So we can rewrite F as
And re-arranging the formula we can calculate the value of the change in momentum:
Rewriting the acceleration as the increment of velocity
But given the definition of momentum:
And re-arranging the formula we can calculate the value of the change in momentum:
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(A) We can solve the problem by using Ohm's law, which states:
where
V is the potential difference across the electrical device
I is the current through the device
R is its resistance
For the heater coil in the problem, we know
and 
, therefore we can rearrange Ohm's law to find the current through the device:
(B) The resistance of a conductive wire depends on three factors. In fact, it is given by:
where
is the resistivity of the material of the wire
L is the length of the wire
A is the cross-sectional area of the wire
Basically, we see that the longer the wire, the larger its resistance; and the larger the section of the wire, the smaller its resistance.
where
V is the potential difference across the electrical device
I is the current through the device
R is its resistance
For the heater coil in the problem, we know
(B) The resistance of a conductive wire depends on three factors. In fact, it is given by:
where
L is the length of the wire
A is the cross-sectional area of the wire
Basically, we see that the longer the wire, the larger its resistance; and the larger the section of the wire, the smaller its resistance.
Answer:
h = 9.57 seconds
Explanation:
It is given that,
Initial speed of Kalea, u = 13.7 m/s
At maximum height, v = 0
Let t is the time taken by the ball to reach its maximum point. It cane be calculated as :
t = 1.39 s
Let h is the height reached by the ball above its release point. It can be calculated using second equation of motion as :
Here, a = -g
h = 9.57 meters
So, the height attained by the ball above its release point is 9.57 meters. Hence, this is the required solution.