A 2-kg brick is moving at a speed of 6 m/s. how large a force F is needed to stop the brick in a time of 7x10^-4 s?
17142
force = rate of change of momentum
F = 2 * 6/(7*10^-4)
To calculate the force needed to stop the brick, you can use Newton's second law of motion, which states that force (F) is equal to mass (m) multiplied by acceleration (a).
First, we need to determine the acceleration of the brick. The acceleration can be calculated using the formula:
a = (final velocity - initial velocity) / time
Given:
Mass of brick (m) = 2 kg
Initial velocity (u) = 6 m/s
Time (t) = 7 × 10^-4 s
Substituting the values into the formula:
a = (0 - 6) m/s / (7 × 10^-4 s)
Simplifying the expression:
a = (-6) m/s / (7 × 10^-4 s)
Now, we can calculate the acceleration:
a = -8571.43 m/s^2
Since the brick is coming to a stop, the acceleration is in the opposite direction to the initial velocity and therefore negative.
Now that we have the acceleration, we can calculate the force using the formula:
F = m * a
Substituting the values:
F = 2 kg * (-8571.43 m/s^2)
Calculating the force:
F = -17142.86 N
Therefore, a force of -17142.86 N is needed to stop the brick in a time of 7 × 10^-4 s. The negative sign indicates that the force is in the opposite direction to the motion of the brick.
To find the force (F) needed to stop the 2-kg brick in a time of 7x10^-4 s, we need to use the equation for force, which is given by Newton's second law:
F = m * a
where F is the force applied, m is the mass of the object, and a is the acceleration.
In this case, since the brick needs to be stopped, its final velocity (vf) will be zero. The initial velocity (vi) is given as 6 m/s. The time taken (t) is given as 7x10^-4 s.
We can find the acceleration (a) using the equation:
a = (vf - vi) / t
Since the final velocity is zero, the equation simplifies to:
a = -vi / t
Substituting the values, we have:
a = -6 / (7x10^-4)
Now we can calculate the acceleration a:
a = -6 / 7x10^-4 = -8571.43 m/s^2
Finally, we can find the force (F) required to stop the brick using Newton's second law:
F = m * a = 2 kg * -8571.43 m/s^2
F = -17142.86 N
Therefore, a force of approximately -17142.86 N (or 17142.86 N in magnitude) is needed to stop the 2-kg brick in a time of 7x10^-4 s.