A 11 g plastic ball is moving to the left at 29 m/s. How much work must be done on the ball to cause it to move to the right at
1 answer:
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Answer:
A)s = 104.16 m
b)s= 104.16 m
Explanation:
Given that
u = 25 m/s
μ = 0.3
The friction force will act opposite to the direction of motion.
Fr= μ m g
Fr= - m a
a=acceleration
μ m g = - m a
a= - μ g
a= - 0.3 x 10 m/s² ( take g= 10 m/s²)
a= - 3 m/s²
The final speed of the mass is zero ,v= 0
We know that
v² = u² +2 a s
s=distance
0² = 25² - 2 x 3 x s
625 = 6 s
s = 104.16 m
By using energy conservation
Work done by all the forces =Change in the kinetic energy
Negative sign because force act opposite to the displacement.
- 3 x 2 x s = - 625
s= 104.16 m
Answer:
a) Δx = 11.6 m
b) t = 3.9 s
Explanation:
a)
- Since the snowmobile is moving at constant speed, and the drive force is 195 N, this means that thereis another force equal and opposite acting on it, according to Newton's 2nd Law, due to there is no acceleration present in the horizontal direction .
- This force is just the force of kinetic friction, and is equal to -195 N (assuming the positive direction as the direction of the movement).
- Once the drive force is shut off, the only force acting on the snowmobile remains the friction force.
- According Newton's 2nd Law, this force is causing a negative acceleration (actually slowing down the snowmobile) that can be found as follows:
- Assuming the friction force keeps constant, we can use the following kinematic equation in order to find the distance traveled under this acceleration before coming to an stop, as follows:
- Taking into account that vf=0, replacing by the given (v₀) and a from (1), we can solve for Δx, as follows:
b)
- We can find the time needed to come to an stop, applying the definition of acceleration, as follows:
- Since we have already said that the snowmobile comes to an stop, this means that vf = 0.
- Replacing a and v₀ as we did in (3), we can solve for Δt as follows:
Answer:
The acceleration of the object is
Explanation:
Given:
Initial velocity of object = 200 feet/second
Final velocity of object = 50 feet/second
Time of travel = 5 seconds
To calculate acceleration of the object we will find the rate of change of velocity with respect to time.
So, acceleration is given by:
where represents final velocity,
represents initial velocity and
is time of travel.
Plugging in values to evaluate acceleration.
The acceleration of the object is (Answer). The negative sign shows the object is slowing down.