Complete question
A 2700 kg car accelerates from rest under the action of two forces. one is a forward force of 1157 newtons provided by traction between the wheels and the road. the other is a 902 newton resistive force due to various frictional forces. how far must the car travel for its speed to reach 3.6 meters per second? answer in units of meters.
Answer:
The car must travel 68.94 meters.
Explanation:
First, we are going to find the acceleration of the car using Newton's second Law:
(1)
with m the mass , a the acceleration and the net force forces that is:
(2)
with F the force provided by traction and f the resistive force:
(2) on (1):
solving for a:
Now let's use the Galileo’s kinematic equation
(3)
With Vo te initial velocity that's zero because it started from rest, Vf the final velocity (3.6) and the time took to achieve that velocity, solving (3) for :
Answer: 3.5 seconds
EXPLANATION:
Using the formula:
v = u + at
And taking the upwards direction as positive, we have the following information:
u = 35 m/s
a = -10m/s^2 (this is acceleration due to gravity)
At the top of its path, the apple will have a velocity of 0 m/s, therefore:
v = 0m/s
Once you substitute everything into the formula, you get:
0 = 35 + (-10)t
Therefore, t = 35/10 = 3.5 seconds
B.
technically it would depend if the resistors were in series or parallel but B is the answer.
Newton’s 2nd law
———
Newton's second law states that the acceleration of an object is directly related to the force on it, and inversely related to the mass of the object. You need more force to move or stop an object with a lot of mass (or inertia) than you need for an object with less mass. .
Given:
v(final velocity)= 7.5 m/s
t(time taken to pedal along)=4.5 s
Displacement (s)=19 m
Now we know that
s=ut+1/2(at^2)
Where s is the displacement measured in m
u is the initial velocity measured in m/sec
a is the acceleration measured in m/s^2.
t is the time taken to cover this distance.
Substituting the given values in the above formula we get
19= 4.5u+1/2(a x 4.5 x 4.5)
20.25 a + 9 u = 38
Now we also know that
v= u + at
Substituting the given values in the above formula we get
7.5= u + 4.5a
Solving for u and a from the above equations we get
u = 0.944m/s
a= 1.45 m/s^2
Thus the initial velocity is 0.944 m/s