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1.1 A car is moving at a constant velocity - NSC Physical Sciences - Question 1 - 2019 - Paper 1
Question 1
1.1 A car is moving at a constant velocity. Which ONE of the following statements about the forces acting on the car is CORRECT? A The net force acting on the car ... show full transcript
Worked Solution & Example Answer:1.1 A car is moving at a constant velocity - NSC Physical Sciences - Question 1 - 2019 - Paper 1
Step 1
Which ONE of the following statements about the forces acting on the car is CORRECT?
Answer
A The net force acting on the car is zero.
Since the car is moving at a constant velocity, it implies that there is no net force acting on it. According to Newton's First Law, an object will remain at rest or in uniform motion unless acted upon by a net external force.
Step 2
Step 3
Step 4
Which ONE of the following statements about the collision of the balls is CORRECT?
Answer
D Total momentum is conserved but total kinetic energy is not conserved and the masses of the balls are equal.
In elastic collisions, total momentum is conserved. However, because ball M comes to rest, some kinetic energy is converted to other forms, indicating that kinetic energy is not conserved.
Step 5
Which ONE of the graphs below shows the CORRECT relationship between the gravitational potential energy (U) and speed and the kinetic energy (K) and speed v, respectively, for the stone?
Answer
Graph A.
As the stone falls, its potential energy decreases while its kinetic energy increases, represented typically in a graph showing inverse relationships.
Step 6
Which ONE of the statements about the electrostatic forces, \( F_{PR} \) which P exerts on R and \( F_{RP} \) which R exerts on P, is CORRECT?
Answer
( F_{PR} = F_{RP} )
By Newton's Third Law, the forces exerted by two charges on each other are equal in magnitude and opposite in direction.
Step 7
Which ONE of the following combinations about the ammeter readings will be CORRECT when switch S is open and when switch S is closed?
Answer
A Ammeter reads only the current in R1.
When switch S is open, the ammeter will only register the current flowing through R1, since there is no path through R2.
Step 8
Which ONE of the following statements about the threshold frequencies of the metals is CORRECT?
Answer
A The threshold frequency of zinc is greater than that of magnesium.
The work function of a metal is directly related to its threshold frequency; therefore, since the work function of zinc is greater than magnesium, its threshold frequency will also be higher.