# AS level physics forces and motion question

A bullet is fired at an angle of 30° to the horizontal ground at a velocity of 200 ms-1.The bullet is in flight for a time t. Air resistance has a negligible effect on the motion of the bullet. What is the correct expression for the horizontal distance R travelled by the bullet?

A. R = 200 x cos30° x t

B. R = 200 x sin30° x t

C. R=((200 x cos30°)^2)/(2x9.81)

D. R=((200 x sin 30°)^2)/(2x 9.81)

The answer is A but I have no ideas on how to get it. Help me please!
A bullet is fired at an angle of 30° to the horizontal ground at a velocity of 200 ms-1.The bullet is in flight for a time t. Air resistance has a negligible effect on the motion of the bullet. What is the correct expression for the horizontal distance R travelled by the bullet?

A. R = 200 x cos30° x t

B. R = 200 x sin30° x t

C. R=((200 x cos30°)^2)/(2x9.81)

D. R=((200 x sin 30°)^2)/(2x 9.81)

The answer is A but I have no ideas on how to get it. Help me please!

Do you know how to find the distance travelled by a particle that is moving at constant velocity or constant speed in the same direction?

It is the same logic for this question.
Original post by Eimmanuel

Do you know how to find the distance travelled by a particle that is moving at constant velocity or constant speed in the same direction?

It is the same logic for this question.

No
No

This is gcse stuff. I recommend that you try to look back at your text.
S = ?
U = 200cos30
V= 200cos30
A = 0
T = t

U is the initial velocity. Now it’s at an angle and we want the horizontal component of the velocity so we do 200 COS 30 for horizontal. If you don’t know how i get this i would recommend going over projectile motion at an angle.

So now we’re looking for the horizontal distance traveled. We also know that the horizontal acceleration must be 0 because it has a uniform velocity (The velocity stays the same). Using this we can use

S = ut +1/2at^2

a is 0 so 1/2at^2 becomes 0 too so its
S = ut + 0
Plug in the values
S = 200cos30 x t