Answer:
27.1 m/s
Explanation:
Given that at a race car driving event, a staff member notices that the skid marks left by the race car are 9.06 m long. The very experienced staff member knows that the deceleration of a car when skidding is -40.52 m/s2.
Using third equation of motion,
V^2 = U^2 + 2aS
Since the car is decelerating, the final velocity V = 0
Substitute all the parameter into the equation above,
0 = U^2 - 2 * 40.52 * 9.06
U^2 = 734.22
U =
U = 27.096
U = 27.1 m/s approximately
Therefore, the staff member can estimate for the original speed of the race car to be 27.1 m/s if it came to a stop during the skid
Answer:
25J
Explanation:
Given parameters:
Mass of the dog = 10kg
Speed of the dog = 5m/s
Unknown:
The minimum energy required to stop the dog = ?
Solution:
The dog is moving with a kinetic energy and to stop the dog, an equal amount of kinetic energy generated must be applied to the dog.
To find the kinetic energy;
K.E = m v²
m is the mass
v is the velocity
Now insert the parameters and solve;
K.E = x 10 x 5 = 25J
1) See three Kepler laws below
2a) Acceleration is
2b) Tension in the string: 27.4 N
3a) Kinetic energy is the energy of motion, potential energy is the energy due to the position
3b) The kinetic energy of the object is 2.25 J
Explanation:
1)
There are three Kepler's law of planetary motion:
2a)
To solve the problem, we have to write the equation of motions for each block along the direction parallel to the incline.
For the block on the right, we have:
(1)
where
is the component of the weight of the block parallel to the incline, with
M = 8.0 kg (mass of the block)
(acceleration of gravity)
T = tension in the string
a = acceleration of the block
For the block on the left, we have similarly
(2)
where
m = 3.5 kg (mass of the block)
From (2) we get
Substituting into (1),
Solving for a,
2b)
The tension in the string can be calculated using the equation
where
m = 3.5 kg (mass of lighter block)
(acceleration found in part 2)
Substituting,
3a)
The kinetic energy of an object is the energy due to its motion. It is calculated as
where
m is the mass of the object
v is its speed
The potential energy is the energy possessed by an object due to its position in a gravitational field. For an object near the Earth's surface, it is given by
where
m is the mass of the object
g is the strength of the gravitational field
h is the heigth of the object relative to the ground
3b)
The kinetic energy of an object is given by
where
m is the mass of the object
v is its speed
For the object in this problem,
m = 500 g = 0.5 kg
v = 3 m/s
Substituting, we find its kinetic energy:
Learn more about acceleration and forces:
And about kinetic energy:
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