C

1003160903

Level: 
C
The graph of a linear function \( f \) passes through the point \( \left[4\sqrt3;2\right] \) and it makes an angle of \( 30^{\circ} \) with the positive direction of \( x \)-axis measured anticlockwise. Choose the correct form of the function \( f \), such that the given property is preserved.
\( f(x)=\frac{\sqrt3}3x-2 \)
\( f(x)=\sqrt3x-10 \)
\( f(x)=\frac{\sqrt3}3x+2 \)
\( f(x)=\sqrt3x+10 \)

1003160902

Level: 
C
Suppose \( f \) is a linear function. If the value of the independent variable \( x \) increases by \( 4 \), the function value decreases by \( 12 \). Choose the correct form of the function \( f \), such that the given property is preserved.
\( f(x)=-3x \)
\( f(x)=3x \)
\( f(x)=3x-12 \)
\( f(x)=-\frac13x \)

1003160901

Level: 
C
Suppose \( f \) is a linear function. If the value of the independent variable \( x \) increases by \( 6 \), the function value increases by \( 18 \). Choose the correct form of the function \( f \), such that the given property is preserved.
\( f(x)=3x+1 \)
\( f(x)=-3x \)
\( f(x)=\frac13x+18 \)
\( f(x)=\frac13x \)

1003108307

Level: 
C
Choose the triple of points, such that the graph of any of the functions \( f(x)=ax^2+c \), where \( a\in\mathbb{R}\setminus{0} \), \( c\in\mathbb{R} \), does not pass through all three points.
\( [-2;5] \), \( [2;1] \), \( [0;3] \)
\( [-2;5] \), \( [2;5] \), \( [0;3] \)
\( [-2;5] \), \( [2;5] \), \( [0;7] \)
\( [-2;5] \), \( [0;0] \), \( [1;1] \)

1103148606

Level: 
C
If an object moving with an initial velocity \( v_0 \) is slowing down at a constant deceleration \( a \), then the distance \( s \) travelled while decelerating is described by the formula \( s=v_0t-\frac12at^2 \), where \( t \) is time of decelerating. Choose the graph, which could represent the dependency of the distance \( s \) on the time \( t \).

1103148605

Level: 
C
Suppose, an object, that is in rest, starts to accelerate with the constant acceleration \( a \). The distance \( s \) travelled by the object in time \( t \) is given by the formula \( s=\frac12at^2 \). You can see the graph of the distance \( s \) on the time \( t \) dependency in the picture. Find the acceleration \( a \) of the object.
\( 8\frac{\mathrm{m}}{\mathrm{s}^2} \)
\( 16\frac{\mathrm{m}}{\mathrm{s}^2} \)
\( 4\frac{\mathrm{m}}{\mathrm{s}^2} \)
\( 2\frac{\mathrm{m}}{\mathrm{s}^2} \)

1103148603

Level: 
C
Consider a simple circuit in which a battery of electromotive force \( U_e \) and internal resistance \( R_i \) drives a current \( I \) through an external resistor of resistance \( R \) (see figure). The external resistor could be for example an electric light, an electric heating element, or, maybe, an electric motor. The basic purpose of the circuit is to transfer energy from the battery to the external resistor, where it actually does something useful for us (e.g. lighting a light bulb, or lifting a weight). \[ \] The power \( P \) transferred to the external resistor is described by the formula \( P=U_eI-R_i I^2 \). What maximum power can be transferred to the external resistor if we have the source with \( R_i=0.25\,\Omega \) and \( U_e=20\,\mathrm{V} \)?
\( 400\,\mathrm{W} \)
\( 80\,\mathrm{W} \)
\( 40\,\mathrm{W} \)
\( 790\,\mathrm{W} \)