Quadratic functions

1103148606

Level: 
C
If an object moving with an initial velocity v0 is slowing down at a constant deceleration a, then the distance s travelled while decelerating is described by the formula s=v0t12at2, 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=12at2. You can see the graph of the distance s on the time t dependency in the picture. Find the acceleration a of the object.
8ms2
16ms2
4ms2
2ms2

1103148604

Level: 
B
The total mechanical energy E of an object is given by the formula E=mgh+12mv2, where m is the mass of the object, g is the acceleration due to gravity (about 10m/s2), h is the height of the object above the ground and v is the velocity of that object. Suppose that an object of the fixed mass m moves horizontally in the constant height h above the ground. Choose the graph, which could represent the dependence between the total mechanical energy (E) and velocity (v) of the object.

1103148603

Level: 
C
Consider a simple circuit in which a battery of electromotive force Ue and internal resistance Ri 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=UeIRiI2. What maximum power can be transferred to the external resistor if we have the source with Ri=0.25Ω and Ue=20V?
400W
80W
40W
790W

1003148602

Level: 
C
Consider an object thrown at an angle of 30 above the horizontal with the initial velocity of 40ms. How long does it take for the object to reach its maximum height? Note: The height y of an object thrown is described by the formula y=v0tsinα12gt2, where v0 is the initial velocity, g is gravitational acceleration (count with the rounded value 10ms2), t is the time period of the object motion in seconds, and α is the angle to the horizontal at which the object is thrown.
2s
4s
8s
1s