Summer School Now Physics

The speed of an aircraft in still air is 200 km h^–1.

The wind blows from the west at a speed of 85.0 km h^–1.

In which direction must the pilot steer the aircraft in order to fly due north?

• 23.0° east of north

• 23.0° west of north

• 25.2° east of north

• 25.2° west of north

Two balls of masses m and 2m with initial velocities 2v and v collides as shown. After the collision, the mass m travels to the right a velocity of v. How much kinetic energy is lost?

• 0.10 mv²

• 0.25 mv²

• 0.33 mv²

• 0.50 mv²

Tags

NGSS.HS-PS2-2

A cell of internal resistance r and electromotive force (e.m.f.) E is connected in series with a resistor of resistance R.

The resistance R and the e.m.f. E remain fixed. The internal resistance r of the cell changes over time.

Which graph best shows the variation of the current I in the circuit with the internal resistance r?

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A skydiver falls from an aircraft that is moving horizontally. The vertical component of the velocity of the skydiver is v. The vertical component of the acceleration of the skydiver is a. Which row describes v and a during the first few seconds after the skydiver leaves the aircraft?

• v constant, a constant

• v constant, a decreasing

• v increasing, a constant

• v increasing, a decreasing

Tags

NGSS.HS-PS2-1

Which graph could show how the resistance R of a filament lamp varies with the applied potential difference (p.d.) V, as V is increased to the normal operating p.d.?

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In the circuit shown, all the resistors are identical and all the ammeters have negligible resistance.

The reading A₁ is 0.6 A. What are the readings on the other ammeters?

• A₂ = 1.0 A; A₃ = 0.3 A; A₄ = 0.1 A

• A₂ = 1.4 A; A₃ = 0.6 A; A₄ = 0.2 A

• A₂ = 1.8 A; A₃ = 0.9 A; A₄ = 0.3 A

• A₂ = 2.2 A; A₃ = 1.2 A; A₄ = 0.4 A

A snooker ball has a mass of 200 g. It hits the cushion of a snooker table and rebounds along its original path.

The ball arrives at the cushion with a speed of 14.0 m s^–1 and then leaves it with a speed of 7.0 m s^–1. The ball and the cushion are in contact for a time of 0.60 s.

What is the average force exerted on the ball by the cushion?

• 1.4 N

• 2.3 N

• 4.2 N

• 7.0 N

Tags

NGSS.HS-PS2-1

Two cells with electromotive forces E₁ and E₂ and internal resistances r₁ and r₂ are connected to a resistor R as shown.

The terminal potential difference across cell 1 is zero.

Which expression gives the resistance of resistor R?

An unstable nucleus of an element decays by emitting an α-particle or a β– particle to become a nucleus of a different element. This nucleus is also unstable and also emits an α-particle or a β– particle. The process continues until an isotope of the original element is produced.

What is the minimum possible number of these particles emitted?

• 2

• 3

• 4

• 5

Tags

NGSS.HS-PS1-8

A proton is made up of two up quarks and one down quark with charges of +2/3, +2/3, and –1/3. 

• True 
• False
• More information is needed