Answer:
k1 + k2
Explanation:
Spring 1 has spring constant k1
Spring 2 has spring constant k2
After being applied by the same force, it is clearly mentioned that spring are extended by the same amount i.e. extension of spring 1 is equal to extension of spring 2.
x1 = x2
Since the force exerted to each spring might be different, let's assume F1 for spring 1 and F2 for spring 2. Hence the equations of spring constant for both springs are
k1 = F1/x -> F1 =k1*x
k2 = F2/x -> F2 =k2*x
While F = F1 + F2
Substitute equation of F1 and F2 into the equation of sum of forces
F = F1 + F2
F = k1*x + k2*x
= x(k1 + k2)
Note that this is applicable because both spring have the same extension of x (I repeat, EXTENTION, not length of the spring)
Considering the general equation of spring forces (Hooke's Law) F = kx,
The effective spring constant for the system is k1 + k2
the neutron I hope i could help :)
Use this formula for an object starting from rest and accelerating:
Distance = (1/2) (acceleration) (time)²
In this problem, the distance is 40 meters, and acceleration is gravity.
So . . .
40 m = (1/2) (9.8 m/s²) (time)²
Divide each side by (4.9 m/s²) :
time² = (40 m) / (4.9 m/s²)
time² = 8.16 sec²
Take the square root of each side :
√(time²) = √(8.16 sec²)
time = 2.86 seconds
Round it to 2.9 sec <em>(choice B)</em>
The angular acceleration is equal to the final angular velocity divided by the time and the average angular velocity is equal to half the final angular velocity. It follows that the rotational kinetic energy given to the flywheel is equal to the work done by the torque.