End of Term LVIth Quiz

A beaker of water sits on a top pan balance. When a student sticks his finger in the water, the reading on the balance

• Increases

• Decreases

• Stays the same

• Increases or decreases depending on the relative depth of the finger and the water

The Sun has an energy output of 3.8 × 10²⁶ W. It has a radius of 7.0 × 10⁵ km. An estimate of the average power produced inside the Sun per m³ is:

• 6.2 × 10⁷ W

• 3.8 × 10³ W

• 1.1 W

• 0.26 W

The Earth has a mass of 6.0 × 10²⁴ kg and an orbital velocity of 30 km s^-1 about the Sun. What is its kinetic energy?

• 2.7 × 10²⁷ J

• 9.0 × 10²⁸ J

• 2.7 × 10³³ J

• 5.4 × 10³³ J

The second is now defined as the duration of 9,192,631,770 periods of radiation corresponding to the transition between two energy levels of the cesium 133 atom. What is the wavelength of the radiation emitted?

• 3.3 cm

• 3.3 mm

• 31 m

• 33 cm

A neutron has a kinetic energy of 1.0 × 10^-7 eV. If moving vertically, how high could it rise in the earth’s gravitational field?

• 6.1 × 10¹⁶ m

• 9.8 × 10¹³ m

• 4.4 m

• 0.98 m

A steel ball-bearing is dropped onto a concrete floor and rebounds to 80% of its initial height. The percentage of the kinetic energy lost in the collision is.

• 80%

• 64%

• 36%

• 20%

The Moon takes 2 minutes to sink below the horizon at the equator when observed at night (about the same time as the Sun takes to set). If the radius of the Earth is 6400 km and the radius of the Moon is 1700 km, what is the angular size of the Earth when observed from the Moon?

• 3.8^o

• 3.5^o

• 1.9^o

• 0.3^o

A bubble is made from a soap film of uniform thickness enclosing a spherical volume of air. If the diameter of the bubble is trebled, the thickness of the soap film, t, will become

• t/27

• t/9

• t/4

• t/3

A 500-kg car is moving at 28 m/s. The driver sees a barrier ahead. If the car takes 95 meters to come to rest, what is the magnitude of the minimum average net force necessary to stop?

• 47.5 N

• 1400 N

• 2060 N

• 19600 N

• 133000 N

A block rests on an incline that makes the angle φ with the horizontal. The block remains at rest as φ is slowly increased. The magnitudes of the normal force and the static frictional force of the incline on the block

• both increase.

• both decrease.

• both remain the same

• increase and decrease, respectively

• decrease and increase, respectively