A car traveling south is 200 kilometers from its starting point after 2 hours. What is the average velocity of the car?
Choose: 100 kilometers/hour south
Answer:
a) 0.0324 rad/s²
b) 2.01 rad/s , the final angular speed gets doubled
Explanation:
w₀ = initial angular speed = 0 rad/s
w = final angular speed = 0.16 rev/s = 0.16 (6.28) = 1.005 rad/s
t = time interval = 31 s
α = angular acceleration
final angular speed is given as
w = w₀ + α t
1.005 = 0 + α (31)
α = 0.0324 rad/s²
b)
After the acceleration is doubled
α' = 2 α = 2 (0.0324) = 0.0648 rad/s²
w' = final angular speed
w'₀ = initial angular speed = 0 rad/s
final angular speed is given as
w = w₀ + α t
w = 0 + (0.0648) (31)
w = 2.01 rad/s
yes the final angular speed gets doubled
Answer: Option C) 9.63 joules
Explanation:
Mass of object = 8.8kg
Speed of object = ?
Kinetic energy = ?
Momentum of the object = 13 kgm/s
Recall that momentum is a product of mass M and speed V of a moving object.
Thus, Momentum = Mass x Speed
13 kgm/s = 8.8kg x V
V = (13kgm/s ➗ 8.8kg)
V = 1.48 m/s
Now, that the speed of the object is known, calculate its kinetic energy. And, its kinetic energy depends on its mass M and speed, V
Thus, Kinetic energy = 1/2 x mv^2
= 1/2 x 8.8kg x (1.48m/s)^2
= 0.5 x 8.8kg x (1.48m/s)^2
= 4.4 x (1.48m/s)^2
= 9.63 joules
Thus, the kinetic energy of the object is
9.63 joules
As we know from the Newton's II law we can say
here if force is unbalanced then it is for sure that net force on the system is non zero
so here the object must have some acceleration here
so here we can say that object must have change in velocity due to unbalanced force present on it
now the correct option in this case must satisfy the change in velocity condition.
SO correct answers will be
<em>Decelerate. </em>
<em>Stop moving. </em>
<em>Start moving. </em>
<em>
Accelerate. </em>
