A 2000kg car is slowed down uniformly from 20m/s to 5 m/s in 4s.
What is the average total force on the car during this time.
To find the average total force on the car, we can use Newton's second law of motion, which states that force (F) is equal to mass (m) multiplied by acceleration (a):
F = m * a
First, let's calculate the acceleration of the car. Since the car is slowing down uniformly, we can use the formula for average acceleration:
a = (vf - vi) / t
Where:
vf = final velocity = 5 m/s
vi = initial velocity = 20 m/s
t = time taken = 4 s
Substituting the values into the formula:
a = (5 - 20) / 4
a = -15 / 4
a = -3.75 m/s²
Note that the negative sign indicates that the car is slowing down.
Now, we can substitute the mass and acceleration into the formula to find the force:
F = (2000 kg) * (-3.75 m/s²)
F = -7500 N
The negative sign implies that the force is acting in the opposite direction of the car's motion, which makes sense since the car is being slowed down. Therefore, the average total force on the car during this time is 7500 Newtons.
To find the average total force on the car during the given time, we can use Newton's second law of motion, which states that the force acting on an object is equal to its mass multiplied by its acceleration.
First, let's find the acceleration of the car.
Given:
Initial velocity, u = 20 m/s
Final velocity, v = 5 m/s
Time, t = 4 s
The formula to calculate acceleration is:
Acceleration (a) = (Change in velocity) / (Time)
= (v - u) / t
Substituting the given values:
a = (5 m/s - 20 m/s) / 4 s
= -15 m/s / 4 s [Note: The negative sign indicates the deceleration of the car.]
Next, let's calculate the average total force on the car.
Using Newton's second law of motion:
Force (F) = mass (m) x acceleration (a)
= 2000 kg x (-15 m/s^2)
Calculating this:
F = -30,000 N
The average total force acting on the car during this time is -30,000 Newtons. The negative sign indicates that the force is directed opposite to the car's motion, which is the case for deceleration.
f = m a = 2E3 kg *
... [(20 m/s - 5 m/s) / 4 s]
answer is in Newtons