2020-Nov-Physics_paper_1__TZ0_HL – All Questions with detailed solution.
Q.1.2020Physics_paper_1TZ0__HL
Topic: Measurements in physics
Discuss: quantity has the same units as those for energy stored per unit volume?
A. Density
B. Force
C. Momentum
D. Pressure
Answer/Explanation
Solution:
$\frac{\text{Energy}}{\text{volume}}$
Unit of energy is same as unit of work ($W=\mathrm{F\cdot s}$) $\Rightarrow [N-m]$
Unit of volume= $m^3$
so ,on dividing $\frac{\mathrm{N}}{m^2}$
Q.2.2020Physics_paper_1__HL
Topic: Forces
Given: mass 8.0 kg is falling vertically through the air. The drag force acting on object is 60 N.
Calculate: best estimate of the acceleration of the object?
A. $\text{Zero}$
B. $2.5 \mathrm{~m} \mathrm{~s}^{-2}$
C. $ 7.5 \mathrm{~m} \mathrm{~s}^{-2}$
D. $ 10 \mathrm{~ms}^{-2}$
Answer/Explanation
Solution:
$\text{acceleration}=\frac{F_{\text{net}}}{\text{ mass}}$
$F_{\text{net}}=80-\text{weight of body }=20 N$
Q.3.2020Physics_paper_1__HL
Topic: Vectors and scalars
Given: body is held in translational equilibrium by three coplanar forces of magnitude 3 N, 4 N and 5 N.
Three statements about these forces are
all forces are perpendicular to each other
the forces cannot act in the same direction
the vector sum of the forces is equal to zero.
Discuss: statements are true?
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
Answer/Explanation
Solution:
An object is in translational equilibrium if the velocity of its translational motion is constant. An object that is not moving or an object that is moving in a straight line at a constant velocity would be considered in translation equilibrium. To be in translational equilibrium, the net force acting on the object must be zero (recall Newton’s first law: if no unbalanced forces act on an object, it does not accelerate).
Conditions for Translational Equilibrium $\Sigma F=0 N$
or equivalently:
$\Sigma F_x=0 N$ and $\Sigma F_y=0 N$
$\Sigma F$ : sum of all forces, in newtons (N)
$\Sigma F_x$ : sum of all force components in $x$ direction, in newtons (N)
$\Sigma F_y:$ sum of all force components in y direction, in newtons (N)
Q.4.2020Physics_paper_1__HL
Topic: Work, energy and power
Given:An object of mass 1 kg is thrown downwards from a height of 20 m. The initial speed of the object is 6 m/ s , object hits the ground at a speed of 20 m/ s. Assume g = 10 m s–2.
Calculate: best estimate of the energy transferred from the object to the air as it falls?
A. $6 \mathrm{~J}$
B. $18 \mathrm{~J}$
C. $182 \mathrm{~J}$
D. $200 \mathrm{~J}$
Answer/Explanation
Solution:
initial kinetic energy will the estimate of the energy transferred from the object to the air as it falls
$(K_i)=\frac{1}{2}m[(6)^2]$
Q.5.2020Physics_paper_1__HL
Topic: Work, energy and power
Given: A car is driven from rest along a straight horizontal road. The car engine exerts a constant driving force. Friction and air resistance are negligible.
Discuss: How does the power developed by the engine change with the distance travelled?
A. Power does not change.
B. Power decreases linearly.
C. Power increase linearly.
D. Power increases non-linearly.
Answer/Explanation
Solution:
$\text{Power}=\text{Force}\times \text{velocity}$
Already given Force is constant it means acceleration will also be.
$\text{distance }=\frac{\mathrm{v}}{\sqrt{2a}}$
$\begin{aligned}
& P=F \cdot v \\
& P=m a \sqrt{2 a \times \mathrm {distance}} \\
& P \propto(\mathrm {distance})^{ \frac{1}{2}}
\end{aligned}$