Physics Semester 1 Review

Convert 5 kilometers to meters.

• 50 meters

• 500 meters

• 5000 meters

• 50000 meters

Answer explanation

To convert kilometers to meters, multiply by 1000. Therefore, 5 kilometers is 5 x 1000 = 5000 meters. The correct answer is 5000 meters.

According to Newton's second law, what is the acceleration of a 10 kg object when a force of 50 N is applied to it?

• 2 m/s^2

• 5 m/s^2

• 10 m/s^2

• 50 m/s^2

Answer explanation

According to Newton's second law, F = ma. Rearranging gives a = F/m. Here, a = 50 N / 10 kg = 5 m/s². Thus, the correct answer is 5 m/s².

Tags

NGSS.MS-PS2-2

A 5 kg object is subjected to a force that causes it to accelerate at 3 m/s². What is the magnitude of the force?

• 5 N

• 10 N

• 15 N

• 20 N

Answer explanation

To find the force, use Newton's second law: F = m * a. Here, m = 5 kg and a = 3 m/s². Thus, F = 5 kg * 3 m/s² = 15 N. Therefore, the correct answer is 15 N.

Tags

NGSS.MS-PS2-2

Convert 0.75 liters to milliliters.

• 75 mL

• 750 mL

• 7500 mL

• 75000 mL

Answer explanation

To convert liters to milliliters, multiply by 1000. Thus, 0.75 liters x 1000 = 750 mL. Therefore, the correct answer is 750 mL.

A projectile is launched with an initial velocity of 25 m/s. The projectile reaches a maximum height of 20 meters. Assuming no air resistance, how much time does it take for the projectile to reach its highest point?

• 1 s

• 2 s

• 2.5 s

• 4 s

Answer explanation

To find the vertical component of the velocity, use the formula: V_y = V * sin(θ). Here, V = 25 m/s and θ = 60°. Thus, V_y = 25 * sin(60°) = 25 * √3/2 ≈ 21.65 m/s, which is the correct answer.

If a 15 kg object experiences a net force of 45 N, what is its acceleration?

• 1 m/s²

• 2 m/s²

• 3 m/s²

• 4 m/s²

Answer explanation

To find acceleration, use Newton's second law: F = ma. Rearranging gives a = F/m. Here, a = 45 N / 15 kg = 3 m/s². Thus, the correct answer is 3 m/s².

Tags

NGSS.MS-PS2-2

Convert 120 minutes to hours.

• 1 hour

• 1.5 hours

• 2 hours

Answer explanation

To convert minutes to hours, divide the number of minutes by 60. Thus, 120 minutes ÷ 60 = 2 hours. Therefore, the correct answer is 2 hours.

A projectile is launched horizontally from a height of 80 meters. How long does it take to reach the ground? (Assume g = - 9.8 m/s^2)

• 2 seconds

• 3 seconds

• 4 seconds

• 5 seconds

Answer explanation

To find the time to reach the ground, use the formula: \( t = \sqrt{\frac{2h}{g}} \). Here, \( h = 80 \) m and \( g = 9.8 \) m/s². This gives \( t = \sqrt{\frac{160}{9.8}} \approx 4 \) seconds.

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

A 20 kg object is accelerated at 2 m/s². What is the force applied to the object?

• 10 N

• 20 N

• 40 N

• 60 N

Answer explanation

To find the force applied to the object, use Newton's second law: F = m * a. Here, m = 20 kg and a = 2 m/s². Thus, F = 20 kg * 2 m/s² = 40 N. Therefore, the correct answer is 40 N.

Tags

NGSS.MS-PS2-2

What is the unit for FORCE? (a)  

• N (Newtons)

• lbs (pounds)

• g (grams)

• m/s (meters per second)

Answer explanation

The unit for force is the Newton (N), which is defined as the force required to accelerate a one-kilogram mass by one meter per second squared. Other options like pounds and grams are not standard units for force.