List of top Biomechanics Questions

Figure 1 depicts an arm holding a ball in static equilibrium. Figure 2 shows the free-body diagram of the lower arm where \(F\) is the force applied by the biceps muscle at an angle of \(\theta = 60\) degrees with respect to the lower arm, and \(R_1\) and \(R_2\) are the reaction forces acting at point O. The weights of the ball and the lower arm are \(W_1 = 50\) Newtons (N) and \(W_2 = 20\) N, respectively. The force exerted by the biceps muscle is \(F =\) N. (Round off to the nearest integer)

Assume the lower arm to be a rigid body.

In the free-body diagram, measured along the lower arm from the pivot O: the biceps force \(F\) acts at \(4\) cm from O; the forearm's weight \(W_2\) acts a further \(12\) cm beyond that (i.e. \(16\) cm from O); and the ball's weight \(W_1\) acts a further \(16\) cm beyond that (i.e. \(32\) cm from O).

Consider an incompressible cylindrical tissue with a diameter of 2 cm and a height of 3 cm. If this tissue is stretched by 10% in the axial direction, its diameter in the stretched configuration is cm.
Assume homogeneous deformation of the tissue.

There is a steady laminar blood flow in a tapered cylindrical vessel of circular cross-section, as shown in the figure below. Two cross-sections, labeled A and B in the figure, have radii \(0.5\) centimeter (cm) and \(0.45\) cm, respectively. If the average flow speed of the blood at cross-section A is \(1\) cm/second, the average flow speed at cross-section B is cm/second. (Round off to one decimal place).

Assume blood to be an incompressible fluid.

Which one of the following options represents the tissues/organs of a healthy adult human, arranged in the correct decreasing order of their Young's modulus?

A uniform shear force of magnitude 0.01 Newton (N) is applied to the top surface of a cubical tissue sample with side of length 1 cm (marked with dashed lines in the figure below). In the deformed configuration (marked with solid lines), the angle \(\theta = 5\) degrees.
The shear modulus of the tissue is kilopascals (kPa).
Assume the tissue to be a linear, isotropic and homogenous elastic solid.

For a tissue with Young's modulus 4 kPa and shear modulus 1.5 kPa, what is the value of the Poisson's ratio?

Consider two cuboidal blocks of volume 1 cm\(^3\) each, one made of gold and the other of undoped silicon. What will happen to the resistivity of these blocks if the temperature is increased from 300 K to 350 K? Choose one of the following.

At time t, the cardiac dipole is oriented at - 45° (minus forty five degrees) to the horizontal axis. The magnitude of the dipole is 3 mV. Assuming Einthoven frontal plane configuration, what is the magnitude (in mV) of the electrical signal in lead II? (Round off the answer to two decimal places.)