If the speed of a sound is 340 m/s, how far from us would a person be if it takes us 5 s to hear her cries?

• 1700m

• 300m

• 4560m

• 1km

Tags

NGSS.HS-PS4-1

The Sun is 150 000 000 km from Earth. Calculate the minutes light takes to reach the Earth. The speed of the light is 3 · 10⁸ m/s.

• 15 min

• 8.33 min

• 20 min

• 3 min

Tags

NGSS.HS-PS4-1

An object is moving with a velocity 10 m/s in the negative direction of axis x. The object is initially at point A in x = 4 m . Find the position of the object at 5 s.

• 37 m

• -46 m

• 20 m

• -20m

An object is moving with a velocity of 23 m/s in the positive direction of axis x. The final position of the object is 8 m. Which was the initial position if the traveled time is 5 s?

• -107 m

• 55m

• 175m

• -68m

An object is moving with constant velocity along axis x. The initial position is 5 m and the final position of the object is 13 m . Which is its velocity if the traveled time is 4 s?

• -2m/s

• 2 m/s

• -3m/s

• 8 m/s

Judith drives from Plymouth to Southampton, a

distance of 260 km, in 4 hours. She then drives from

Southampton to London, a distance of 145 km, in 1

hour and 30 minutes. Determine her average speed

for each journey.

• 1) She drove with an average speed of 65 Km/h in the first part and 96,7 Km/h in the second part.

• 2) The total average speed of the journey is 80,8 Km/h

• 3) None of the previous answers.

• 4) The 1st and 2nd choice are right.

A car is at rest and in10 seconds reaches a velocity of 20m/s. Which is its acceleration?

• 2 m/s²

• 2 m/s

• 3 m/s²

• 5 m/s²

Tags

NGSS.HS-PS2-1

A lorry is travelling at a velocity of 25 m/sand finds an object on the road and the driver has to brake to stop in 10 seconds. What is its acceleration?

• -2.5 m/s²

• -2.5 m/s

• 6 m/s²

• -6 m/s²

Tags

NGSS.HS-PS2-1

En el movimiento rectilíneo uniforme MRU, la aceleración es

• Nula

• Positiva

• Negativa

• Depende del ejercicio

Tags

NGSS.HS-PS2-1

Si la velocidad de un móvil disminuye, su aceleración será

• Positiva

• Negativa

• Positiva y negativa

• No se puede determinar

Tags

NGSS.HS-PS2-1