Physics Answers

The velocity of a 2kg object increases from 2.0m/s to 4.0m/s by a constant force. Find the change in momentum of the object. Show complete solution.

Find the momentum of a 100kg object travelling at a speed of 20m/s. Show complete solution.

A roller coaster ride in a park includes a vertical drop of 60m. Assume that the roller coaster has a speed of nearly zero when it reaches the top of the hill. Neglected friction, find the speed of the riders at the bottom of the hill. Show complete solution.

A 5m rope is tied to a tree limb and used as a swing. Tarzan holds the rope in horizontal orientation. Assuming that the frictional force is zero and there is no air resistance, determine the speed of Tarzan at the lowest point on the circular arc of the swing. Show complete solution.

Find the minimum kinetic energy (in MeV) in the lab system needed by an alpha particle to cause

the reaction:

7𝑁

14 + 𝛼 → 8𝑂

17 + 1𝐻

1

Given that: m(

14N) = 14.00307 u; m(α) 4.003879 u; m(

1H) = 1.00783 u; m(

17O) = 17.0013 u;

1 𝑢 = 931.5 𝑀𝑒𝑉/𝑐

2

Starting from rest, an object accelerates on a straight level surface at the rate of 2 m/s2 for 10 s.What is the speed of the object at the end of 10 s?

 A turtle crawls along a straight line, which we will call the x-axis with the positive direction to the right. The equation for the turtle’s position as a function of time is x(t) = 50.0 cm + (2.00 cm/s)t – (0.0625 cm/𝑠2)𝑡2. (a) Find the turtle’s initial velocity, initial position, and initial acceleration. (b) At what time t is the velocity of the turtle zero? (c) How long after starting does it take the turtle to return to its starting point? (d) At what times t is the turtle a distance of 10.00 cm from its starting point? What is the velocity at each of these times?

Given that: 𝐴= 2i + 9j +3k and 𝐵= -i – 4k . Find 𝐴 𝑋𝐵

Can you explain this to me.

The planet Earth has 5.2 times the radius of Krypton, but has the same mass. If an object weighs 288 pounds on Krypton, how many pounds would it weigh on the Earth?

Give the answer as an integer in ordinary (not scientific) notation.

4. A spaceship racing towards Jupiter at 0.70c launches a probe towards the planet at a relative speed of 0.50c. How fast will the probe approach Jupiter as measured by the observer on that planet?

A. 1.4 c

B. -3.3 c

C. 0.89 c

D. 0.78 c

5. An astronaut journeying to the nearby star Alpha Centauat at a speed of 0.99 c relative to the Earth requires 8.57 Earth years to complete hertrip How many years as measured on earth to complete her trip?

A. 1:21 years

B. 60.75 years

C. 5 years

D. 50 years