Physics Answers

A projectile is fired at an angle 15 ° from a gun that is 45 m above the flat ground, emerging

from the gun with a speed of 300 m/s.

(a) How long does the projectile remain in air?

(b) At what horizontal distance from the firing ground does it strike the ground.

(c) What is the velocity of the projectile when it hits the ground?

A particle moves in a straight line such that its displacement, x meters, from a fixed point O

on the line at time t seconds is given by 𝑥 = 60[𝑒

−2𝑡 − 𝑒

−4𝑡

].

(a) Find the time when the particle is instantaneously at rest.

(b) Find the displacement of the particle from O when t = 4 s.

(c) Find the total distance travelled during the first 4 seconds of its motion.

An ice glider is traveling 35 degrees W of S at 6 m/s when the wind exerts a force of 860 N 18 degrees N of W for three seconds. The mass of the glider is 215 kg. Complete the chart below and then answer the questions that follow.

t(s): 0, 1, 2, 3

East v (m/s): --3.44, t = 1, t = 2, t = 3

North v (m/s): --4.92, t = 1, t = 2, t = 3

What is the glider's initial kinetic energy?

What is the glider's kinetic energy at t = 2?

How much energy does the wind put into the glider in the 3 s interval?

What is the glider's average speed for the three second interval?

What is the glider's average velocity for the three second interval?

What do you mean by the Young’s modulus for steel is 𝒀 = 𝟐. 𝟎 × 𝟏𝟎𝟏𝟏 𝑵𝒎−𝟐

?

A 6.61 kg pendulum hangs in an elevator. The tension in the string supporting the pendulum if the elevator moves upward with a constant acceleration of 2.41 m/s² is ab.c N [up]. Input the values of a, b and c into the blank and use the guidelines below:

• Do not include a positive or negative sign.
• Include a decimal in your answer.
• Use a acceleration value of 9.81 m/s²
• Let up be positive

Write down five real life applications of surface tension.

Illustrate the stress and strain of solids

Write a short note on polymer materials and amorphous solid.

Gold has a face centered cubic unit cell and has the density 𝟏𝟗. 𝟑 𝒈 𝒄𝒎−𝟑. Calculate the length along an edge. (𝐴𝑢 = 197 𝑔 𝑚𝑜𝑙−1)

What do you mean by the Young’s modulus for steel is 𝒀 = 𝟐. 𝟎 × 𝟏𝟎𝟏𝟏 𝑵𝒎−𝟐 ? Explain briefly.