Projectile Motion
A golf ball reaches its highest point in the air. What is its vertical acceleration at that instant?
−9.8 m s⁻²
A 2 kg object is placed on a frictionless incline at an angle θ. Which expression correctly gives its acceleration?
A. mgsinθ
B. mgcosθ
C. gsinθ
D. gcosθ
C. gsinθ
Two equal masses mmm separated by distance r exert a gravitational force F on each other. What is the gravitational force between masses m and 2m separated by the same distance?
A. 1/4*F
B. 1/2*F
C. 2F
D. 4F
C. 2F
Two identical charges repel each other with a force of 16 N. What is the new force if the distance between the charges is doubled?
4 N
If you approach a lamp while travelling at seven-tenths the speed of light (0.7c), you will measure the speed of light from the lamp to be:
A. 0.3c
B. 0.70c
C. 1.0c
D. 1.7c
C. 1.0c
A projectile is launched horizontally from a cliff. If the horizontal launch speed doubles, what happens to the time of flight and the horizontal range?
Time stays the same, range doubles
A block slides down an incline even though friction is present. Which relationship must be true?
A. Fp>Ff
B. FP=Ff
C. FP<Ff
D. FP=Ff=0
A. Fp>Ff
Explanation:
The parallel component of gravity must be greater than friction for the block to accelerate down the incline.
A comet in a highly elliptical orbit approaches the Sun. According to Kepler’s Second Law, what happens to its speed?
A. It slows down
B. It stays constant
C. It speeds up
D. It stops momentarily
C. It speeds up
Explanation:
Objects move faster when they are closer to the Sun because gravity is stronger there.
Two oppositely charged particles attract each other. If the force on Q1 is 10 N, what is the force on Q2?
10 N
The proper time interval (t0) is the elapsed time between two events measured in a frame of reference in which the two events:
A. are simultaneous.
B. occur at the same time.
C. are measured with synchronised clocks.
D. occur at the same point in space.
D. occur at the same point in space
A cricket ball leaves the bat at 60 m s⁻¹ at an angle of 30° above the horizontal. What is the magnitude of its initial vertical velocity component?
30 m s⁻¹
A 30 kg box slides down a frictionless incline angled at 35 degrees. Determine the acceleration of the box.
Use: g=9.8 m s-2
5.6 m s⁻²
Mars orbits the Sun at 1.524 times Earth’s orbital radius. Determine the orbital period of Mars.
A. 1.23 years
B. 1.32 years
C. 1.88 years
D. 3.53 years
C. 1.88 years
A +1.5 C charge moves through a potential difference of 6 V. How much energy is transferred?
9 J
A train travelling at 0.9c along a straight track approaches a crossing light that flashes once per second. An observer on the train will measure the time between flashes to be:
A. somewhat greater than one second.
B. equal to one second.
C. somewhat less than one second.
D. much greater than one second.
D. much greater than one second
A soccer ball is kicked at 30.0 m s⁻¹ at an angle of 20.0°. Determine the maximum height reached by the ball.
Use: g=9.8 m/s^2
5.4 m
A 400 g mass rests on a frictionless 30° incline and is connected over a pulley to a hanging 200 g mass. What happens to the 400 g mass?
A. Moves at constant speed up the incline
B. Moves at constant speed down the incline
C. Remains stationary
D. Accelerates down the incline
C. Remains stationary
A planet has an elliptical orbit around its star. At its average distance from the star, its speed is 15 km s⁻¹. What is the planet’s speed most likely to be when it is nearest the star?
20 km s⁻¹
The electric field strength at point R is 18 N C⁻¹. Point S is twice as far from the positive charge as point R. What is the electric field strength at point S?
4.5 N C⁻¹
The lifetime of a subatomic particle is measured in a lab to be 4.2 x 10-7 while travelling at 0.55c. Determine its proper lifetime interval (t0).
3.5 x 10-7
A wedding ring is thrown horizontally from a window 15 m above the ground and lands 7.5 m from the base of the building. Determine the horizontal throwing speed.
Use: g=9.8 m/s^2
4.3 m s⁻¹
A person pulls a 100 kg box up a 35 degrees incline at constant speed using a rope angled 20 degrees above the incline. Friction is 650 N. Determine the applied force FA.
Use: g=9.8 m s-2
1500 N
Planet X has mass M and radius R. Planet Y has mass 10M and radius 4R. Determine the ratio:
(gY)/(gX)
A. 0.5
B. 1.6
C. 2.0
D. 2.5
A. 0.5
Two suspended spheres are 2.0 cm apart. Sphere A has charge +2.0×10-4 C and sphere B has charge −4.0×10-5 C. Determine the force between them.
A. 180 N attractive
B. 180 N repulsive
C. 1800 N repulsive
D. 1800 N attractive
D. 1800 N attractive
A subatomic pion has a rest life of 2.6 x 10-8, but to a laboratory observer, it appears to live for 5.2 x 10-8
Calculate the speed of the pion in terms of (c).
0.866c