2. A body with a mass of 490kg is pulled along a horizontal plane at a constant velocity.the pulling force is 1.2 kN is making an angle of 20degrees with the plane.
A.determine the coefficient of friction
3.a force of 318.123N accelerates a car at 3m/s^2 from rest for 10seconds
Calculate the following
A. Mass of the car
B.momentum of the car after 10 seconds
C.velocity of the car after 10seconds
See Related questions: 2-26-15, 11:06 AM.
To determine the coefficient of friction in question 2, we can use the formula:
coefficient of friction = (frictional force) / (normal force)
First, let's determine the frictional force. Since the body is being pulled at a constant velocity on a horizontal plane, the frictional force must be equal to the pulling force to maintain the constant velocity. The pulling force is given as 1.2 kN (kilonewtons), which is equivalent to 1200 N (since 1 kN = 1000 N).
So, the frictional force is 1200 N.
The normal force is the force exerted by the surface upward to counteract the weight of the body. Since the body is on a horizontal plane, the normal force is equal in magnitude and opposite in direction to the weight of the body.
The weight of the body can be found using the formula:
weight = mass * acceleration due to gravity
In this case, the acceleration due to gravity is approximately 9.8 m/s^2.
weight = 490 kg * 9.8 m/s^2 = 4802 N
Therefore, the normal force is 4802 N.
Finally, we can calculate the coefficient of friction:
coefficient of friction = 1200 N / 4802 N ≈ 0.2497
Thus, the coefficient of friction is approximately 0.2497.
Moving on to question 3:
A. We can use Newton's second law of motion, which states that force equals mass multiplied by acceleration (F = ma). Rearranging the formula, we have mass (m) = force (F) / acceleration (a).
In this case, the force is given as 318.123 N, and the acceleration is given as 3 m/s^2.
mass = 318.123 N / 3 m/s^2 ≈ 106.041 kg
Therefore, the mass of the car is approximately 106.041 kg.
B. Momentum (p) is defined as mass (m) multiplied by velocity (v). We already know the mass of the car, and to find the velocity after 10 seconds, we can use the formula:
velocity (v) = initial velocity (u) + (acceleration (a) * time (t))
Given that the car starts from rest, the initial velocity (u) is 0 m/s. The acceleration is given as 3 m/s^2, and the time (t) is 10 seconds.
velocity (v) = 0 m/s + (3 m/s^2 * 10 s) = 30 m/s
Therefore, the velocity of the car after 10 seconds is 30 m/s.
Now we can calculate the momentum of the car:
momentum (p) = mass (m) * velocity (v)
momentum (p) = 106.041 kg * 30 m/s ≈ 3181.23 kg * m/s
Therefore, the momentum of the car after 10 seconds is approximately 3181.23 kg * m/s.
C. We already calculated the velocity of the car in part B, which is 30 m/s.
Therefore, the velocity of the car after 10 seconds is 30 m/s.