A spider accelerates from a standstill to 5m/s in 10s. What is its acceleration?
1 answer:
Answer:
Acceleration = 0.5m/s²
Explanation:
Given the following data;
Final velocity = 5m/s
Time = 10 seconds
Since the spider started from rest, its initial velocity is equal to 0m/s
To find the acceleration;
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Mathematically, acceleration is given by the equation;
Where,
a is acceleration measured in
v and u is final and initial velocity respectively, measured in
t is time measured in seconds.
Substituting into the equation, we have;
Acceleration = 0.5m/s²
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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:
The work required is -515,872.5 J
Explanation:
Work is defined in physics as the force that is applied to a body to move it from one point to another.
The total work W done on an object to move from one position A to another B is equal to the change in the kinetic energy of the object. That is, work is also defined as the change in the kinetic energy of an object.
Kinetic energy (Ec) depends on the mass and speed of the body. This energy is calculated by the expression:
where kinetic energy is measured in Joules (J), mass in kilograms (kg), and velocity in meters per second (m/s).
The work (W) of this force is equal to the difference between the final value and the initial value of the kinetic energy of the particle:
In this case:
- W=?
- m= 2,145 kg
- v2= 12
- v1= 25
Replacing:
W= -515,872.5 J
<u><em>The work required is -515,872.5 J</em></u>